Transiently-operated desalination systems with heat recovery and associated methods

ABSTRACT

Systems and methods related to desalination systems are described herein. According to some embodiments, the desalination systems are transiently operated and/or configured to facilitate transient operation. In some embodiments, a liquid stream comprising water and at least one dissolved salt is circulated through a fluidic circuit comprising a desalination system. In some embodiments, a portion of the desalination system (e.g., a humidifier) is configured to remove at least a portion of the water from the liquid stream to produce a concentrated brine stream enriched in the dissolved salt. In certain cases, the concentrated brine stream is recirculated through the fluidic circuit until the concentrated brine stream reaches a relatively high density (e.g., at least about 10 pounds per gallon) and/or a relatively high salinity (e.g., a total dissolved salt concentration of at least about 25 wt %). In certain embodiments, additional salt is added to the concentrated brine stream to produce an ultra-high-density brine stream (e.g., a brine stream having a density of at least about 11.7 pounds per gallon). Some aspects relate to a system that is configured to promote energy efficiency by recovering heat from the recirculated concentrated brine stream upon discharge from the fluidic circuit.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/719,189, filed May 21, 2015, and entitled “Transiently-OperatedDesalination Systems with Heat Recovery and Associated Methods,” whichis incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

Systems and methods related to the desalination of aqueous streamscomprising at least one salt and the production of saturated brines aregenerally described.

BACKGROUND

Desalination is a process by which an amount of at least one salt isremoved from an aqueous stream. For example, seawater, brackish water,flowback water, industrial wastewater, and/or water produced from oiland gas extraction processes can be desalinated to produce fresh watersuitable for human consumption, irrigation, and/or industrial use.

As the world's population has expanded, the demand for fresh water hasincreased. Desalination may play a role in satisfying this increaseddemand. In addition, desalination may play a role in recyclingwastewater that has been produced by various human processes (e.g.,industrial processes, oil and gas extraction processes), therebymitigating the need to dispose of such wastewater. Accordingly, improveddesalination systems and methods are desirable.

SUMMARY

Systems and methods related to the desalination of aqueous streamscomprising at least one salt and the production of saturated brines aregenerally described. The subject matter of the present inventioninvolves, in some cases, interrelated products, alternative solutions toa particular problem, and/or a plurality of different uses of one ormore systems and/or articles.

Certain aspects relate to a method for producing a concentrated brinestream. In some embodiments, the method comprises supplying a firstliquid stream comprising water and at least one dissolved salt at aninitial concentration to a fluidic circuit. The fluidic circuit may, insome cases, comprise a humidifier, which may remove at least a portionof the water from the first liquid stream to produce a firstconcentrated brine stream comprising water and the at least onedissolved salt at a second concentration higher than the initialconcentration of the first liquid stream. In certain embodiments, themethod further comprises recirculating the first concentrated brinestream through the fluidic circuit to remove at least a portion of thewater from the first concentrated brine stream, forming a recirculatedfirst concentrated brine stream comprising water and the at least onedissolved salt at a third concentration higher than the secondconcentration of the first concentrated brine stream. In someembodiments, the method comprises discharging the recirculated firstconcentrated brine stream from the fluidic circuit when the recirculatedfirst concentrated brine stream reaches a density of at least about 10pounds per gallon.

In certain embodiments, the method comprises supplying a first liquidstream comprising water and at least one dissolved salt at an initialconcentration to a fluidic circuit comprising a humidifier, wherein thehumidifier removes at least a portion of the water from the first liquidstream to produce a first concentrated brine stream comprising water andthe at least one dissolved salt at a second concentration higher thanthe initial concentration of the first liquid stream. In some cases, themethod further comprises recirculating the first concentrated brinestream through the fluidic circuit to remove at least a portion of thewater from the first concentrated brine stream, forming a recirculatedfirst concentrated brine stream comprising water and the at least onedissolved salt at a third concentration higher than the secondconcentration of the first concentrated brine stream. In certain cases,the method comprises discharging the recirculated first concentratedbrine stream from the fluidic circuit when the salinity reaches at leastabout 25%.

According to some embodiments, the method comprises supplying a firstliquid stream comprising water and a dissolved salt at an initialconcentration to a fluidic circuit comprising a humidifier, wherein thehumidifier removes at least a portion of the water from the first liquidstream to produce a first concentrated brine stream comprising water andthe dissolved salt at a second concentration higher than the initialconcentration of the first liquid stream. In some cases, the methodfurther comprises recirculating the first concentrated brine streamthrough the fluidic circuit to remove at least a portion of the waterfrom the first concentrated brine stream, forming a recirculated firstconcentrated brine stream comprising water and the dissolved salt at athird concentration higher than the second concentration of the firstconcentrated brine stream. In certain embodiments, the method furthercomprises discharging the recirculated first concentrated brine streamfrom the fluidic circuit when the recirculated first concentrated brinestream reaches a density of at least about 10 pounds per gallon, whereindischarging the recirculated first concentrated brine stream comprisesflowing the recirculated first concentrated brine stream through a firstportion of a heat exchanger. In some embodiments, the method furthercomprises supplying a second liquid stream comprising water and adissolved salt at an initial concentration to the fluidic circuitcomprising the humidifier, wherein supplying the second liquid streamcomprises flowing the second liquid stream through a second portion ofthe heat exchanger, wherein heat is transferred from the recirculatedfirst concentrated brine stream to the second liquid stream in the heatexchanger, and wherein the humidifier removes at least a portion of thewater from the second liquid stream to produce a second concentratedbrine stream comprising water and the dissolved salt at a secondconcentration higher than the initial concentration of the second liquidstream. According to certain embodiments, the method further comprisesrecirculating the second concentrated brine stream through the fluidiccircuit to remove at least a portion of the water from the secondconcentrated brine stream, forming a recirculated second concentratedbrine stream comprising water and the dissolved salt at a thirdconcentration higher than the second concentration of the secondconcentrated brine stream. In some cases, the method further comprisesdischarging the recirculated second concentrated brine stream from thefluidic circuit when the recirculated second concentrated brine streamreaches a density of at least about 10 pounds per gallon.

In certain embodiments, the method comprises supplying a first liquidstream comprising water and a dissolved salt at an initial concentrationto a feed tank. In some embodiments, the method further comprisesflowing the first liquid stream from the feed tank to a fluidic circuitcomprising a humidifier, wherein the humidifier removes at least aportion of the water from the first liquid stream to produce a firstconcentrated brine stream comprising water and the dissolved salt at asecond concentration higher than the initial concentration of the firstliquid stream. In some cases, the method further comprises recirculatingthe first concentrated brine stream through the fluidic circuit toremove at least a portion of the water from the first concentrated brinestream, forming a recirculated first concentrated brine streamcomprising water and the dissolved salt at a third concentration higherthan the second concentration of the first concentrated brine stream. Incertain embodiments, the method further comprises discharging therecirculated first concentrated brine stream from the fluidic circuitwhen the recirculated first concentrated brine stream reaches a densityof at least about 10 pounds per gallon, wherein discharging therecirculated first concentrated brine stream comprises flowing therecirculated first concentrated brine stream through a first portion ofa heat exchanger to a concentrated brine tank. In some embodiments, themethod further comprises supplying a second liquid stream comprisingwater and a dissolved salt at an initial concentration to the feed tank,wherein supplying the second liquid stream comprises flowing the secondliquid stream through a second portion of the heat exchanger, whereinheat is transferred from the recirculated first concentrated brinestream to the second liquid stream in the heat exchanger. In certainembodiments, the method further comprises flowing the second liquidstream from the feed tank to the fluidic circuit comprising thehumidifier, wherein the humidifier removes at least a portion of thewater from the second liquid stream to produce a second concentratedbrine stream comprising water and the dissolved salt at a secondconcentration higher than the initial concentration of the second liquidstream. In some embodiments, the method further comprises recirculatingthe second concentrated brine stream through the fluidic circuit toremove at least a portion of the water from the second concentratedbrine stream, forming a recirculated second concentrated brine streamcomprising water and the dissolved salt at a third concentration higherthan the second concentration of the second concentrated brine stream.In some embodiments, the method further comprises discharging therecirculated second concentrated brine stream from the fluidic circuitwhen the recirculated second concentrated brine stream reaches a densityof at least about 10 pounds per gallon, wherein discharging therecirculated second concentrated brine stream comprises flowing therecirculated second concentrated brine stream through the first portionof the heat exchanger to the concentrated brine tank. In certainembodiments, the method further comprises flowing a first volume ofliquid from the concentrated brine tank to the first portion of the heatexchanger while flowing a second volume of liquid from the feed tank tothe second portion of the heat exchanger, wherein heat is transferredfrom the first volume of liquid to the second volume of liquid.

Some aspects relate to a system for producing a concentrated brinestream. In some embodiments, the system comprises a first tank; a secondtank; a heat exchanger fluidly connected to the first tank and thesecond tank; and a desalination system fluidly connected to the firsttank and the second tank. In certain cases, the desalination system isconfigured to receive a feed stream comprising water and at least onedissolved salt and produce a water-containing stream lean in the atleast one dissolved salt relative to the feed stream and a concentratedsaline stream enriched in the at least one dissolved salt relative tothe feed stream.

Certain aspects relate to a method for producing a concentrated brinestream. In some embodiments, the method comprises supplying a liquidstream comprising water and a dissolved salt at an initial concentrationto a fluidic circuit comprising a humidifier, wherein the humidifierremoves at least a portion of the water from the liquid stream toproduce a concentrated brine stream comprising water and the dissolvedsalt at a second concentration higher than the initial concentration ofthe liquid stream. In some embodiments, the method further comprisesrecirculating the concentrated brine stream through the fluidic circuitto remove at least a portion of the water from the concentrated brinestream, forming a recirculated concentrated brine stream comprisingwater and the dissolved salt at a third concentration higher than thesecond concentration of the concentrated brine stream. In certain cases,the method further comprises discharging the recirculated concentratedbrine stream from the fluidic circuit when the recirculated concentratedbrine stream reaches a density of at least about 10 pounds per gallon.In certain embodiments, the method further comprises adding additionalsalt to the recirculated concentrated brine stream until therecirculated concentrated brine stream reaches a density of at leastabout 11.7 pounds per gallon.

Other advantages and novel features of the present invention will becomeapparent from the following detailed description of various non-limitingembodiments of the invention when considered in conjunction with theaccompanying figures. In cases where the present specification and adocument incorporated by reference include conflicting and/orinconsistent disclosure, the present specification shall control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIG. 1A shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a humidifier, accordingto some embodiments;

FIG. 1B shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a humidifier, aconduit, and a plurality of valves, according to some embodiments;

FIG. 1C shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a feed tank and ahumidifier, according to some embodiments;

FIG. 1D shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a feed tank, ahumidifier, a conduit, and a plurality of valves, according to someembodiments;

FIG. 2 shows a schematic flow diagram, according to some embodiments, ofan exemplary humidification-dehumidification desalination systemcomprising a humidifier and a dehumidifier;

FIG. 3A shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising two feed tanks, adesalination system, and a heat exchanger configured to recover heatfrom a discharged concentrated brine stream, according to someembodiments;

FIG. 3B shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a feed tank, aconcentrated brine tank, a desalination system, and a counter-flow heatexchanger, according to some embodiments;

FIG. 3C shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a feed tank, aconcentrated brine tank, a desalination system comprising threedesalination units, and a parallel-flow heat exchanger, according tosome embodiments;

FIG. 4 shows a schematic flow diagram, according to some embodiments, ofan exemplary system for producing a concentrated brine stream comprisinga pretreatment system, a desalination system, and a precipitationapparatus;

FIG. 5 shows a schematic flow diagram of an exemplary separationapparatus, according to some embodiments;

FIG. 6 shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a feed tank, adesalination system, a pump, and a plurality of valves, according tosome embodiments;

FIG. 7 shows, according to some embodiments, a schematic flow diagram ofan exemplary system for producing a concentrated brine stream comprisingtwo feed tanks, a desalination system, and a heat exchanger; and

FIG. 8 shows a schematic flow diagram of an exemplary system forproducing a concentrated brine stream comprising a feed tank, aconcentrated brine tank, a desalination system comprising threedesalination units, and a heat exchanger, according to some embodiments.

DETAILED DESCRIPTION

Systems and methods related to desalination systems, includingtransiently-operated desalination systems, are described herein.According to some embodiments, a liquid stream comprising water and atleast one dissolved salt is circulated through a desalination system. Insome embodiments, a portion of the desalination system (e.g., ahumidifier) is configured to remove at least a portion of the water fromthe liquid stream to produce a concentrated brine stream enriched in thedissolved salt relative to the liquid stream. In certain cases, theconcentrated brine stream is recirculated through the desalinationsystem (e.g. through a fluidic circuit passing through a humidifier ofthe desalination system) until the recirculated concentrated brinestream reaches a relatively high density (e.g., at least about 10 poundsper gallon) and/or a relatively high salinity (e.g., a total dissolvedsalt concentration of at least about 25 wt %). In certain embodiments,one or more additional salts are added to the recirculated concentratedbrine stream to produce an ultra-high-density concentrated brine stream(e.g., a brine stream having a density of at least about 11.7 pounds pergallon). Some aspects relate to a system that is configured to promoteenergy efficiency by recovering heat from the recirculated concentratedbrine stream, e.g. upon or after discharge from a humidifier of thedesalination system.

As used herein, a transiently-operated desalination system refers to adesalination system in which a liquid stream is recirculated through thedesalination system until a certain condition is met (e.g., until theliquid stream reaches a certain density and/or salinity). Uponsatisfaction of the condition, the liquid stream may be discharged fromthe desalination system. In contrast, a continuously-operateddesalination system generally refers to a desalination system in which aliquid stream is fed to the desalination system, desalinated, andsubsequently discharged from the desalination system without beingrecirculated.

It has been discovered within the context of this invention that atransiently-operated desalination system may be particularly well-suitedfor producing a concentrated brine stream (e.g., a brine stream having arelatively high density and/or salinity). In some cases, it may beadvantageous for a desalination system to produce concentrated brine, asthe concentrated brine may be a highly desirable product that can beused in a variety of applications. For example, concentrated brine canbe used in the oil and gas industry as a kill fluid (e.g., ahigh-density fluid placed in a wellbore to stop the flow of reservoirfluids) and/or as a drilling fluid (e.g., a fluid that assists indrilling a wellbore). In addition, concentrated brine can be used in theproduction of chemicals, textiles, and/or leather. In some cases,concentrated brine solutions can be used to de-ice roads, as suchsolutions may be capable of de-icing a road faster than a solid salt.

In addition, it may be advantageous for a desalination system to produceconcentrated brine not only because the concentrated brine is a valuableproduct, but because it avoids the need to dispose of the concentratedbrine as a liquid waste stream. In some cases, disposal of liquid wastestreams may be expensive and/or complicated. For example, one method ofdisposing of a liquid waste stream in an oilfield is deep wellinjection. Deep well injection sites often are expensive to drill,heavily taxed and regulated, and/or of limited capacity. Accordingly, insome cases it may be desirable to avoid the need to dispose of liquidwaste streams or reduce the volume of such liquid waste streamsrequiring disposal.

Continuously-operated desalination systems described in the prior artmay be less suitable for producing concentrated brine or may be unableto produce concentrated brine without undesirable complications. Forexample, because concentrated brine solutions are generally near, at, orabove the saturation limit, production of concentrated brine oftenresults in the formation of salt crystals. The formation of saltcrystals in a desalination system may be deleterious, as the saltcrystals may clog pumps, instruments, valves, and/or separation surfacesof the desalination system.

However, it has been discovered that a transiently-operated desalinationsystem may be capable of producing concentrated brine while eliminatingor reducing at least some such complications. In a transiently-operateddesalination system, the concentration of one or more salts in a liquidstream circulating through the desalination system generally varies overtime. In some cases, the amount of time that a liquid stream having arelatively high concentration of one or more salts spends in atransiently-operated desalination system (e.g., residence time) is lessthan the amount of time that an equivalent liquid stream would spend ina continuously-operated desalination system seeking to produceconcentrated brine. In certain embodiments, a liquid stream flowingthrough a transiently-operated desalination system may have a relativelyhigh flow velocity, which may inhibit formation of salt crystals.Accordingly, the probability of forming salt crystals within adesalination system may be reduced in a transiently-operateddesalination system compared to a continuously-operated desalinationsystem. In addition, in some transiently-operated desalination systemsof the invention, fouling of the desalination system by salt crystalformation may be avoided by following a period of high salinityoperation with a period of low salinity operation. In some suchtransiently-operated desalination systems, salt crystals that formduring a period of high salinity operation may be dissolved during aperiod of low salinity operation.

In some cases, transient operation of a desalination system to produce aconcentrated brine stream may be associated with further advantages. Forexample, a transiently-operated desalination system may have flexibilityto produce a concentrated brine stream from a variety of types of feedstreams. In the oil and gas industry, for example, one type of feedstream that may be encountered is produced water (e.g., water thatemerges from oil or gas wells along with the oil or gas). Due to thelength of time produced water has spent in the ground, and due to highsubterranean pressures and temperatures that may increase the solubilityof certain salts and minerals, produced water often comprises relativelyhigh concentrations of dissolved salts and minerals. For example, someproduced water streams may comprise a supersaturated solution ofdissolved strontium sulfate (SrSO₄). In contrast, another type of feedstream that may be encountered in the oil and gas industry is flowbackwater (e.g., water that is injected as a fracking fluid during hydraulicfracturing operations and subsequently recovered). Flowback water oftencomprises a variety of constituents used in fracking, includingsurfactants, proppants, and viscosity reducing agents, but often has alower salinity than produced water. In some cases, atransiently-operated desalination system advantageously has theflexibility to produce concentrated brine from feed streams havingdifferent salinities. For example, in a transiently-operateddesalination stream, a feed stream may be concentrated via successivepasses through the desalination system until a certain condition is met,regardless of the initial salinity of the feed stream.

An exemplary schematic diagram of a desalination system configured to betransiently operated to produce a concentrated brine stream is shown inFIG. 1A. In FIG. 1A, system 100 for producing a concentrated brinestream comprises a fluidic circuit (102, 104, 106, 108) comprising ahumidifier 102, which may be configured to remove at least a portion ofwater from a liquid stream comprising water and at least one dissolvedsalt at an initial concentration to produce a concentrated brine streamenriched in the at least one dissolved salt. In some embodiments,humidifier 102 is part of a desalination system (e.g., ahumidification-dehumidification (HDH) desalination system). Accordingly,in certain embodiments, humidifier 102 is fluidly connected to adehumidifier (not shown in FIG. 1A), which may be configured to producea stream comprising substantially pure water. As shown in FIG. 1A,humidifier 102 is fluidly connected to conduit 108 via humidifier inlet104 and humidifier outlet 106. Conduit 108 is also fluidly connected toinlet 110 and outlet 112. In some embodiments, inlet 110 is fluidlyconnected to a source of a liquid comprising water and at least onedissolved salt (not shown in FIG. 1A).

In operation, a liquid stream comprising water and at least onedissolved salt may enter system 100 through inlet 110. The liquid streammay flow through conduit 108 and enter humidifier 102 through humidifierinlet 104. In humidifier 102, at least a portion of the water may beremoved from the liquid stream to produce a concentrated brine stream.The concentrated brine stream may then exit humidifier 102 throughhumidifier outlet 106 and be recirculated through the fluidic circuit(e.g. via conduit 108 back to humidifier inlet 104). The recirculatedconcentrated brine stream may continue to recirculate through thefluidic circuit of system 100 until a certain condition is met (e.g.,until a certain density or salinity is reached). Upon satisfaction ofthe condition, the recirculated concentrated brine stream may bedischarged from the fluidic circuit through outlet 112.

In some embodiments, system 100 further comprises a plurality ofoptional valves to regulate flow through the system. For example, asshown in FIG. 1B, optional inlet valve 114 is positioned after inlet110, optional discharge valve 116 is positioned before outlet 112, andoptional recirculation valve 118 is positioned along conduit 108. Inoperation, inlet valve 114 and recirculation valve 118 may initially beopen and discharge valve 116 may initially be closed, and a liquidstream comprising water and at least one dissolved salt may enter thefluidic circuit through inlet 110. After the liquid stream has enteredthe fluidic circuit, inlet valve 114 may be closed. The liquid streammay then flow through conduit 108 and enter humidifier 102 throughhumidifier inlet 104. At least a portion of the water may be removedfrom the liquid stream to produce a concentrated brine stream inhumidifier 102, and the concentrated brine stream may exit humidifier102 through humidifier outlet 106. The concentrated brine stream maysubsequently be recirculated through the fluidic circuit until a certaincondition is satisfied. Upon satisfaction of the condition, dischargevalve 116 may be opened and recirculation valve 118 may be closed, andthe recirculated concentrated brine stream may be discharged from thefluidic circuit through outlet 112.

According to some embodiments, system 100 further comprises an optionalfeed tank. For example, FIG. 1C shows an exemplary schematicillustration of system 100 comprising feed tank 120 and humidifier 102.As shown in FIG. 1C, feed tank 120 is fluidly connected to inlet 110,which may be in fluid communication with a source of a liquid comprisingwater and at least one dissolved salt (not shown in FIG. 1C). Feed tank120 is also fluidly connected to humidifier inlet 104 and humidifieroutlet 106 through conduit 108.

In operation, a liquid stream comprising water and at least onedissolved salt may enter feed tank 120 through inlet 110. The liquidstream may then flow through conduit 108 from feed tank 120 tohumidifier inlet 104. In humidifier 102, an amount of water may beremoved from the liquid stream to produce a concentrated brine stream.The concentrated brine stream may exit humidifier 102 through humidifieroutlet 106 and may be returned to feed tank 120 through conduit 108. Insome embodiments, an additional amount of the liquid comprising waterand at least one dissolved salt may be added to feed tank 120 throughinlet 110. In certain embodiments, the additional amount of liquid maybe added to maintain a constant volume of liquid circulating throughfeed tank 120. In some cases, the additional amount of liquid mayprevent cavitation at the inlet of a pump (not shown in FIG. 1C)configured to pump liquid from feed tank 120 to humidifier 102. Theconcentrated brine stream, along with the added amount of liquid, may berecirculated through the fluidic circuit (120, 108, 104, 102, 106) ofsystem 100 until a certain condition is met. Upon satisfaction of thecondition, the recirculated concentrated brine stream may be dischargedfrom the fluidic circuit through outlet 112.

In some embodiments, the system further comprises an optional feed tankand a plurality of optional valves to regulate flow through the fluidiccircuit. For example, in FIG. 1D, optional inlet valve 114 is positionedafter inlet 110, which is fluidly connected to optional feed tank 120.Optional feed tank 120 is also fluidly connected to humidifier 102through conduit 108. Optional recirculation valve 118 is positionedalong conduit 108. Optional discharge valve 116 is positioned beforeoutlet 112, which is in fluid communication with conduit 108.

In operation, feed tank 120 may initially be filled with a liquid streamcomprising water and at least one dissolved salt. Recirculation valve118 may initially be open, and inlet valve 114 and discharge valve 116may initially be closed. The liquid stream may flow through conduit 108from feed tank 120 to humidifier 102, where at least a portion of thewater may be removed from the liquid stream to produce a concentratedbrine stream. The concentrated brine stream may exit humidifier 102 andreturn to feed tank 120 via conduit 108. In some embodiments, inletvalve 114 may be opened, and an additional amount of liquid comprisingwater and at least one dissolved salt may be added to feed tank 120.Inlet valve 114 may then be closed. The concentrated brine stream maythen be recirculated through the fluidic circuit (120, 108, 104, 102,106) of system 100 until a certain condition is met. When the conditionis satisfied, recirculation valve 118 may be closed, and discharge valve116 may be opened. The recirculated concentrated brine stream may thenbe discharged from the fluidic circuit. Inlet valve 114 may then beopened, and feed tank 120 may be filled with a second liquid streamcomprising water and at least one dissolved salt.

The liquid stream comprising water and at least one dissolved salt fedto the system for producing a concentrated brine stream can originatefrom a variety of sources. For example, in certain embodiments, at leasta portion of the liquid stream that enters a fluidic circuit comprisingat least a portion of a desalination system comprises and/or is derivedfrom seawater, produced water, flowback water, ground water, brackishwater, and/or wastewater (e.g., industrial wastewater). Non-limitingexamples of wastewater include textile mill wastewater, leather tannerywastewater, paper mill wastewater, cooling tower blowdown water, fluegas desulfurization wastewater, landfill leachate water, and/or theeffluent of a chemical process (e.g., the effluent of anotherdesalination system and/or a chemical process). As described in furtherdetail herein, at least a portion of the liquid stream may be pretreatedto remove at least a portion of one or more components (e.g., a scalingion, a water-immiscible material, a suspended solid, and/or a volatileorganic material).

According to some embodiments, the liquid stream fed to the system forproducing a concentrated brine stream comprises water and at least onedissolved salt at an initial concentration. A dissolved salt generallyrefers to a salt that has been solubilized to such an extent that thecomponent ions of the salt are no longer ionically bonded to each other.In certain embodiments, at least one dissolved salt in the liquid streamis a monovalent salt. As used herein, the term “monovalent salt” refersto a salt that includes a monovalent cation (e.g., a cation with a redoxstate of +1 when solubilized). Examples of monovalent salts include, butare not limited to, salts containing sodium, potassium, lithium,rubidium, cesium, and francium. In certain embodiments, the monovalentsalts include monovalent anions comprising, for example, chlorine,bromine, fluorine, and iodine. Non-limiting examples of monovalent saltsinclude sodium chloride (NaCl), sodium bromide (NaBr), potassiumchloride (KCl), potassium bromide (KBr), sodium carbonate, (Na₂CO₃), andsodium sulfate (Na₂SO₄). In some cases, at least one salt is a divalentsalt. As used herein, the term “divalent salt” refers to a salt thatincludes a divalent cation (e.g., a cation with a redox state of +2 whensolubilized). Non-limiting examples of divalent salts include calciumchloride (CaCl₂), calcium sulfate (CaSO₄), magnesium sulfate (MgSO₄),strontium sulfate (SrSO₄), barium sulfate (BaSO₄), and barium-strontiumsulfate (BaSr(SO₄)₂). In some cases, at least one salt in the liquidstream is a trivalent salt (e.g., a salt that includes a trivalentcation having a redox state of +3 when solubilized) or a tetravalentsalt (e.g., a salt that includes a tetravalent cation having a redoxstate of +4 when solubilized). Non-limiting examples of trivalent saltsor tetravalent salts that may be present in certain liquid streamsinclude iron (III) hydroxide (Fe(OH)₃), iron (III) carbonate(Fe₂(CO₃)₃), aluminum hydroxide (Al(OH)₃), aluminum carbonate(Al₂(CO₃)₃), boron salts, and/or silicates.

The liquid stream fed to the system for producing a concentrated brinestream may have any initial salinity. As used herein, the salinity of aliquid stream refers to the weight percent (wt %) of all dissolved saltsin the liquid stream. In some embodiments, the liquid stream has asalinity of at least about 1%, at least about 5%, at least about 10%, atleast about 15%, at least about 20%, at least about 25%, at least about26%, at least about 27%, at least about 28%, at least about 29%, or atleast about 30% (and/or, in certain embodiments, up to the solubilitylimit of the dissolved salt(s) in the liquid stream). In someembodiments, the liquid stream has a salinity of about 30% or less,about 29% or less, about 28% or less, about 27% or less, about 26% orless, about 25% or less, about 20% or less, about 15% or less, about 10%or less, about 5% or less, or about 1% or less. Combinations of theabove-noted ranges are also possible. For example, in some embodiments,the liquid stream may have a salinity in the range of about 1 wt % toabout 10 wt %, about 1 wt % to about 20 wt %, about 1 wt % to about 25wt %, about 1 wt % to about 26 wt %, about 1 wt % to about 27 wt %,about 1 wt % to about 28 wt %, about 1 wt % to about 29 wt %, about 1 wt% to about 30 wt %, about 10 wt % to about 20 wt %, about 10 wt % toabout 25 wt %, about 10 wt % to about 26 wt %, about 10 wt % to about 27wt %, about 10 wt % to about 28 wt %, about 10 wt % to about 29 wt %,about 10 wt % to about 30 wt %, about 20 wt % to about 25 wt %, about 20wt % to about 26 wt %, about 20 wt % to about 27 wt %, about 20 wt % toabout 28 wt %, about 20 wt % to about 29 wt %, about 20 wt % to about 30wt %, about 25 wt % to about 26 wt %, about 25 wt % to about 27 wt %,about 25 wt % to about 28 wt %, about 25 wt % to about 29 wt %, or about25 wt % to about 30 wt %. Salinity may be measured according to anymethod known in the art. For example, a non-limiting example of asuitable method for measuring salinity is the SM 2540C method. Accordingto the SM 2540C method, a sample comprising an amount of liquidcomprising one or more dissolved solids is filtered (e.g., through aglass fiber filter), and the filtrate is evaporated to dryness in aweighed dish at 180° C. The increase in dish weight represents the massof the total dissolved solids in the sample. The salinity of the samplemay be obtained by dividing the mass of the total dissolved solids bythe mass of the original sample and multiplying the resultant number by100.

According to some embodiments, the initial concentration of at least onedissolved salt (e.g., NaCl) in the liquid stream fed to the system forproducing a concentrated brine stream is relatively high. In someembodiments, the initial concentration of at least one dissolved salt(e.g., NaCl) in the liquid stream fed to the system for producing aconcentrated brine stream is at least about 100 mg/L, at least about 200mg/L, at least about 500 mg/L, at least about 1,000 mg/L, at least about2,000 mg/L, at least about 5,000 mg/L, at least about 10,000 mg/L, atleast about 20,000 mg/L, at least about 50,000 mg/L, at least about75,000 mg/L, or at least about 100,000 mg/L, at least about 102,000mg/L, at least about 110,000 mg/L, at least about 120,000 mg/L, at leastabout 150,000 mg/L, at least about 175,000 mg/L, at least about 200,000mg/L, at least about 210,000 mg/L, at least about 219,000 mg/L, at leastabout 220,000 mg/L, at least about 250,000 mg/L, at least about 275,000mg/L, at least about 300,000 mg/L, at least about 310,000 mg/L, at leastabout 312,000 mg/L, at least about 320,000 mg/L, at least about 350,000mg/L, or at least about 375,000 mg/L (and/or, in certain embodiments, upto the solubility limit of the salt in the liquid stream). In someembodiments, the initial concentration of at least one dissolved salt inthe liquid stream is in the range of about 100 mg/L to about 375,000mg/L, about 1,000 mg/L to about 10,000 mg/L, about 1,000 mg/L to about50,000 mg/L, about 1,000 mg/L to about 75,000 mg/L, about 1,000 mg/L toabout 100,000 mg/L, about 1,000 mg/L to about 150,000 mg/L, about 1,000mg/L to about 200,000 mg/L, about 1,000 mg/L to about 250,000 mg/L,about 1,000 mg/L to about 300,000 mg/L, about 1,000 mg/L to about350,000 mg/L, about 1,000 mg/L to about 375,000 mg/L, about 10,000 mg/Lto about 50,000 mg/L, about 10,000 mg/L to about 75,000 mg/L, about10,000 mg/L to about 100,000 mg/L, about 10,000 mg/L to about 150,000mg/L, about 10,000 mg/L to about 200,000 mg/L, about 10,000 mg/L toabout 250,000 mg/L, about 10,000 mg/L to about 300,000 mg/L, about10,000 mg/L to about 350,000 mg/L, about 10,000 mg/L to about 375,000mg/L, about 50,000 mg/L to about 100,000 mg/L, about 50,000 mg/L toabout 150,000 mg/L, about 50,000 mg/L to about 200,000 mg/L, about50,000 mg/L to about 250,000 mg/L, about 50,000 mg/L to about 300,000mg/L, about 50,000 mg/L to about 350,000 mg/L, about 50,000 mg/L toabout 375,000 mg/L, about 100,000 mg/L to about 150,000 mg/L, about100,000 mg/L to about 200,000 mg/L, about 100,000 mg/L to about 250,000mg/L, about 100,000 mg/L to about 300,000 mg/L, about 100,000 mg/L toabout 350,000 mg/L, about 100,000 mg/L to about 375,000 mg/L, about102,000 mg/L to about 219,000 mg/L, about 102,000 mg/L to about 312,000mg/L, about 150,000 mg/L to about 200,000 mg/L, about 150,000 mg/L toabout 250,000 mg/L, about 150,000 mg/L to about 300,000 mg/L, about150,000 mg/L to about 350,000 mg/L, about 150,000 mg/L to about 375,000mg/L, about 200,000 mg/L to about 250,000 mg/L, about 200,000 mg/L toabout 300,000 mg/L, about 200,000 mg/L to about 350,000 mg/L, about200,000 mg/L to about 375,000 mg/L, about 250,000 mg/L to about 300,000mg/L, about 250,000 mg/L to about 350,000 mg/L, about 250,000 mg/L toabout 375,000 mg/L, about 300,000 mg/L to about 350,000 mg/L, or about300,000 mg/L to about 375,000 mg/L. The concentration of a dissolvedsalt generally refers to the combined concentrations of the cation andanion of the salt. For example, the concentration of dissolved NaClwould refer to the sum of the concentration of sodium ions (Na⁺) and theconcentration of chloride ions (Cl⁻). The concentration of a dissolvedsalt may be measured according to any method known in the art. Forexample, suitable methods for measuring the concentration of a dissolvedsalt include inductively coupled plasma (ICP) spectroscopy (e.g.,inductively coupled plasma optical emission spectroscopy). As onenon-limiting example, an Optima 8300 ICP-OES spectrometer may be used.

In some embodiments, the liquid stream fed to the system for producing aconcentrated brine stream comprises at least one dissolved salt (e.g.,NaCl) in an amount of at least about 1 wt %, at least about 5 wt %, atleast about 10 wt %, at least about 15 wt %, at least about 20 wt %, atleast about 25 wt %, at least about 26 wt %, at least about 27 wt %, atleast about 28 wt %, at least about 29 wt %, or at least about 30 wt %(and/or, in certain embodiments, up to the solubility limit of the saltin the liquid stream). In some embodiments, the liquid stream fed to thesystem for producing a concentrated brine stream comprises at least onedissolved salt in an amount in the range of about 1 wt % to about 10 wt%, about 1 wt % to about 20 wt %, about 1 wt % to about 25 wt %, about 1wt % to about 26 wt %, about 1 wt % to about 27 wt %, about 1 wt % toabout 28 wt %, about 1 wt % to about 29 wt %, about 1 wt % to about 30wt %, about 10 wt % to about 20 wt %, about 10 wt % to about 25 wt %,about 10 wt % to about 26 wt %, about 10 wt % to about 27 wt %, about 10wt % to about 28 wt %, about 10 wt % to about 29 wt %, about 10 wt % toabout 30 wt %, about 20 wt % to about 25 wt %, about 20 wt % to about 26wt %, about 20 wt % to about 27 wt %, about 20 wt % to about 28 wt %,about 20 wt % to about 29 wt %, about 20 wt % to about 30 wt %, about 25wt % to about 26 wt %, about 25 wt % to about 27 wt %, about 25 wt % toabout 28 wt %, about 25 wt % to about 29 wt %, or about 25 wt % to about30 wt %.

In some embodiments, the initial total dissolved salt concentration ofthe liquid stream fed to the system for producing a concentrated brinestream may be relatively high. The total dissolved salt concentrationgenerally refers to the combined concentrations of all the cations andanions of dissolved salts (e.g., monovalent, divalent, trivalent, and/ortetravalent salts) present in the liquid stream. As a simple,non-limiting example, in a water stream comprising dissolved NaCl anddissolved MgSO₄, the total dissolved salt concentration would refer tothe total concentrations of the Na⁺, Cl⁻, Mg²⁺, and SO₄ ²⁻ ions. Incertain cases, the initial total dissolved salt concentration of theliquid stream fed to the system for producing a concentrated brinestream is at least about 1,000 mg/L, at least about 2,000 mg/L, at leastabout 5,000 mg/L, at least about 10,000 mg/L, at least about 20,000mg/L, at least about 50,000 mg/L, at least about 75,000 mg/L, at leastabout 100,000 mg/L, at least about 110,000 mg/L, at least about 120,000mg/L, at least about 150,000 mg/L, at least about 175,000 mg/L, at leastabout 200,000 mg/L, at least about 210,000 mg/L, at least about 220,000mg/L, at least about 250,000 mg/L, at least about 275,000 mg/L, at leastabout 300,000 mg/L, at least about 310,000 mg/L, at least about 320,000mg/L, at least about 350,000 mg/L, at least about 375,000 mg/L, at leastabout 400,000 mg/L, at least about 450,000 mg/L, or at least about500,000 mg/L (and/or, in certain embodiments, up to the solubility limitof the dissolved salt(s) in the liquid stream). In some embodiments, theinitial total dissolved salt concentration of the liquid stream is inthe range of about 1,000 mg/L to about 10,000 mg/L, about 1,000 mg/L toabout 20,000 mg/L, about 1,000 mg/L to about 50,000 mg/L, about 1,000mg/L to about 75,000 mg/L, about 1,000 mg/L to about 100,000 mg/L, about1,000 mg/L to about 150,000 mg/L, about 1,000 mg/L to about 200,000mg/L, about 1,000 mg/L to about 250,000 mg/L, about 1,000 mg/L to about300,000 mg/L, about 1,000 mg/L to about 350,000 mg/L, about 1,000 mg/Lto about 400,000 mg/L, about 1,000 mg/L to about 450,000 mg/L, about1,000 mg/L to about 500,000 mg/L, about 10,000 mg/L to about 20,000mg/L, about 10,000 mg/L to about 50,000 mg/L, about 10,000 mg/L to about75,000 mg/L, about 10,000 mg/L to about 100,000 mg/L, about 10,000 mg/Lto about 150,000 mg/L, about 10,000 mg/L to about 200,000 mg/L, about10,000 mg/L to about 250,000 mg/L, about 10,000 mg/L to about 300,000mg/L, about 10,000 mg/L to about 350,000 mg/L, about 10,000 mg/L toabout 400,000 mg/L, about 10,000 mg/L to about 450,000 mg/L, about10,000 mg/L to about 500,000 mg/L, about 20,000 mg/L to about 50,000mg/L, about 20,000 mg/L to about 75,000 mg/L, about 20,000 mg/L to about100,000 mg/L, about 20,000 mg/L to about 150,000 mg/L, about 20,000 mg/Lto about 200,000 mg/L, about 20,000 mg/L to about 250,000 mg/L, about20,000 mg/L to about 300,000 mg/L, about 20,000 mg/L to about 350,000mg/L, about 20,000 mg/L to about 400,000 mg/L, about 20,000 mg/L toabout 450,000 mg/L, about 20,000 mg/L to about 500,000 mg/L about 50,000mg/L to about 100,000 mg/L, about 50,000 mg/L to about 150,000 mg/L,about 50,000 mg/L to about 200,000 mg/L, about 50,000 mg/L to about250,000 mg/L, about 50,000 mg/L to about 300,000 mg/L, about 50,000 mg/Lto about 350,000 mg/L, about 50,000 mg/L to about 400,000 mg/L, about50,000 mg/L to about 450,000 mg/L, about 50,000 mg/L to about 500,000mg/L, about 100,000 mg/L to about 150,000 mg/L, about 100,000 mg/L toabout 200,000 mg/L, about 100,000 mg/L to about 250,000 mg/L, about100,000 mg/L to about 300,000 mg/L, about 100,000 mg/L to about 350,000mg/L, about 100,000 mg/L to about 400,000 mg/L, about 100,000 mg/L toabout 450,000 mg/L, or about 100,000 mg/L to about 500,000 mg/L. Totaldissolved salt concentration may be measured according to any methodknown in the art. For example, a non-limiting example of a suitablemethod for measuring total dissolved salt concentration is the SM 2540Cmethod. According to the SM 2540C method, a sample comprising an amountof liquid comprising one or more dissolved solids is filtered (e.g.,through a glass fiber filter), and the filtrate is evaporated to drynessin a weighed dish at 180° C. The increase in dish weight represents themass of the total dissolved solids in the sample. The total dissolvedsalt concentration of the sample may be obtained by dividing the mass ofthe total dissolved solids by the volume of the original sample.

In some embodiments, the liquid stream comprising water and at least onedissolved salt initially fed to the system for producing a concentratedbrine stream is made to flow through at least a portion of adesalination system (e.g., a system configured to remove at least aportion of at least one salt from an aqueous stream). In someembodiments, the desalination system comprises one or more desalinationunits. According to certain embodiments, at least one of thedesalination units is a thermal desalination unit. In some cases, atleast one of the desalination units is a humidification-dehumidification(HDH) desalination unit. An HDH desalination unit generally refers to aunit comprising a humidifier and a dehumidifier. In some embodiments,the humidifier is configured to receive a liquid feed stream comprisingwater and at least one dissolved salt and to transfer at least a portionof the water from the liquid feed stream to a carrier gas through anevaporation process, thereby producing a humidified gas stream and aconcentrated brine stream. In certain embodiments, the carrier gascomprises a non-condensable gas. Non-limiting examples of suitablenon-condensable gases include air, nitrogen, oxygen, helium, argon,carbon monoxide, carbon dioxide, sulfur oxides (SO_(x)) (e.g., SO₂,SO₃), and/or nitrogen oxides (NO_(x)) (e.g., NO, NO₂). In someembodiments, the dehumidifier is configured to receive the humidifiedgas stream from the humidifier and to transfer at least a portion ofwater from the humidified gas stream to a stream comprisingsubstantially pure water through a condensation process.

FIG. 2 shows an exemplary schematic illustration of HDH desalinationunit 200, which may be used in association with certain inventivesystems and methods described herein. In FIG. 2, desalination unit 200comprises humidifier 102 and dehumidifier 202. As shown in FIG. 2,humidifier 102 comprises liquid inlet 104 (which may correspond, forexample, to humidifier inlet 104 from FIG. 1) and liquid outlet 106(which may correspond, for example, to humidifier outlet 106 from FIG.1). In FIG. 2, humidifier 102 is fluidly connected to dehumidifier 202via gas conduits 204 and 206. As shown in FIG. 2, dehumidifier 202comprises liquid inlet 208 and liquid outlet 210.

In operation, a liquid stream comprising water and a dissolved salt atan initial concentration may enter humidifier 102 through liquid inlet104. Humidifier 102 may also be configured to receive a carrier gasstream comprising a non-condensable gas. According to some embodiments,humidifier 102 is configured such that the liquid stream comes intocontact (e.g., direct or indirect contact) with the carrier gas stream,and heat and water vapor are transferred from the liquid stream to thecarrier gas stream through an evaporation process, thereby producing ahumidified gas stream. In some embodiments, the remaining portion of theliquid stream that is not transported to the carrier gas stream forms aconcentrated brine stream enriched in the salt relative to the liquidstream (e.g., the concentration of the salt in the concentrated brinestream is greater than the initial concentration of the salt in theliquid stream). In some embodiments, the concentrated brine stream exitshumidifier 102 through liquid outlet 106, which may be fluidly connectedto a conduit corresponding to conduit 108 in FIG. 1.

According to some embodiments, the humidified gas stream exitshumidifier 102 and flows through gas conduit 204 to dehumidifier 202. Astream comprising substantially pure water may enter dehumidifier 202through liquid inlet 208. In dehumidifier 202, the humidified gas streammay come into contact (e.g., direct or indirect contact) with thesubstantially pure water stream, and heat and water may be transferredfrom the humidified gas stream to the substantially pure water streamthrough a condensation process, thereby producing a dehumidified gasstream. The stream comprising substantially pure water may exitdehumidifier 202 through liquid outlet 210. In some cases, at least aportion of the substantially pure water stream may be discharged fromHDH desalination system 200. In certain embodiments, at least a portionof the substantially pure water stream may be recirculated to liquidinlet 208. The dehumidified gas stream may exit dehumidifier 202, and atleast a portion of the dehumidified gas stream may return to humidifier102 through gas conduit 206. In some embodiments, at least a portion ofthe dehumidified gas stream may be transported elsewhere within thesystem and/or vented.

A humidifier (e.g., a humidifier of an HDH desalination unit) in asystem for producing a concentrated brine stream may have anyconfiguration that allows for the transfer of water vapor from a liquidfeed stream to a carrier gas stream (e.g., through an evaporationprocess). In certain embodiments, the humidifier comprises a vessel(e.g., a stainless steel tank or other vessel). The humidifier vesselcan comprise a liquid inlet configured to receive a liquid feed streamcomprising water and at least one dissolved salt and a gas inletconfigured to receive a carrier gas stream. In some embodiments, thehumidifier can further comprise a liquid outlet and a gas outlet.

A dehumidifier (e.g., a dehumidifier of an HDH desalination unit) in asystem for producing a concentrated brine stream may have anyconfiguration that allows for the transfer of water from a humidifiedgas stream to a stream comprising substantially pure water (e.g.,through a condensation process). In certain embodiments, thedehumidifier comprises a vessel (e.g., a stainless steel tank or othervessel). The dehumidifier vessel can comprise a liquid inlet configuredto receive a stream comprising substantially pure water and a gas inletconfigured to receive the humidified gas stream. In some embodiments,the dehumidifier can further comprise a liquid outlet for the streamcomprising substantially pure water and a gas outlet for thedehumidified gas stream.

According to some embodiments, the humidifier is a bubble columnhumidifier (e.g., a humidifier in which the evaporation process occursthrough direct contact between a liquid feed stream and bubbles of acarrier gas) and/or the dehumidifier is a bubble column dehumidifier(e.g., a dehumidifier in which the condensation process occurs throughdirect contact between a substantially pure liquid stream and bubbles ofa humidified gas). In some cases, bubble column humidifiers and bubblecolumn dehumidifiers may be associated with certain advantages. Forexample, bubble column humidifiers and dehumidifiers may exhibit higherthermodynamic effectiveness than certain other types of humidifiers(e.g., packed bed humidifiers, spray towers, wetted wall towers) anddehumidifiers (e.g., surface condensers). Without wishing to be bound bya particular theory, the increased thermodynamic effectiveness may be atleast partially attributed to the use of gas bubbles for heat and masstransfer in bubble column humidifiers and dehumidifiers, since gasbubbles may have more surface area available for heat and mass transferthan many other types of surfaces (e.g., metallic tubes, liquid films,packing material). In addition, bubble column humidifiers anddehumidifiers may have certain features that further increasethermodynamic effectiveness, including, but not limited to, relativelylow liquid level height, relatively high aspect ratio liquid flow paths,and multi-staged designs.

In certain embodiments, a bubble column humidifier comprises at leastone stage comprising a chamber and a liquid layer positioned within aportion of the chamber. The liquid layer may, in some cases, comprise aliquid comprising water and at least one dissolved salt. The chamber mayfurther comprise a gas distribution region occupying at least a portionof the chamber not occupied by the liquid layer. In addition, thechamber may be in fluid communication with a bubble generator (e.g., asparger plate). In some embodiments, a carrier gas stream flows throughthe bubble generator, forming bubbles of the carrier gas. The carriergas bubbles may then travel through the liquid layer. The liquid layermay be maintained at a temperature higher than the temperature of thegas bubbles, and as the gas bubbles directly contact the liquid layer,heat and/or mass may be transferred from the liquid layer to the gasbubbles. In some cases, at least a portion of water may be transferredto the gas bubbles through an evaporation process. The bubbles of thehumidified gas may exit the liquid layer and enter the gas distributionregion. The humidified gas may be substantially homogeneouslydistributed throughout the gas distribution region. The humidified gasmay then exit the bubble column humidifier as a humidified gas stream.

In some embodiments, a bubble column dehumidifier comprises at least onestage comprising a chamber and a liquid layer positioned within aportion of the chamber. The liquid layer may, in some cases, comprisesubstantially pure water. The chamber may further comprise a gasdistribution region occupying at least a portion of the chamber notoccupied by the liquid layer. In addition, the chamber may be in fluidcommunication with a bubble generator (e.g., a sparger plate). In someembodiments, the humidified gas stream flows from the humidifier throughthe bubble generator, forming bubbles of the humidified gas. The bubblesof the humidified gas may then travel through the liquid layer. Theliquid layer may be maintained at a temperature lower than thetemperature of the humidified gas bubbles, and as the humidified gasbubbles directly contact the liquid layer, heat and/or mass may betransferred from the humidified gas bubbles to the liquid layer via acondensation process.

Suitable bubble column condensers that may be used as the dehumidifierand/or suitable bubble column humidifiers that may be used as thehumidifier in certain systems and methods described herein include thosedescribed in U.S. Pat. No. 8,523,985, by Govindan et al., issued Sep. 3,2013, and entitled “Bubble-Column Vapor Mixture Condenser”; U.S. Pat.No. 8,778,065, by Govindan et al., issued Jul. 15, 2014, and entitled“Humidification-Dehumidification System Including a Bubble-Column VaporMixture Condenser”; U.S. Patent Publication No. 2013/0074694, byGovindan et al., filed Sep. 23, 2011, and entitled “Bubble-Column VaporMixture Condenser”; U.S. Patent Publication No. 2014/0367871, byGovindan et al., filed Jun. 12, 2013, and entitled “Multi-Stage BubbleColumn Humidifier”; U.S. Patent Publication No. 2015/0083577, filed onSep. 23, 2014, and entitled “Desalination Systems and AssociatedMethods”; U.S. Patent Publication No. 2015/0129410, filed on Sep. 12,2014, and entitled “Systems Including a Condensing Apparatus Such as aBubble Column Condenser,” each of which is incorporated herein byreference in its entirety for all purposes.

In some embodiments, the humidifier and/or dehumidifier comprise aplurality of stages. For example, the stages may be arranged such that agas (e.g., a carrier gas, a humidified gas) flows sequentially from afirst stage to a second stage. In some cases, the stages may be arrangedin a vertical fashion (e.g., a second stage positioned above a firststage) or a horizontal fashion (e.g., a second stage positioned to theright or left of a first stage). In some cases, each stage may comprisea liquid layer. In embodiments relating to a humidifier comprising aplurality of stages (e.g., a multi-stage humidifier), the temperature ofthe liquid layer of the first stage (e.g., the bottommost stage in avertically arranged bubble column) may be lower than the temperature ofthe liquid layer of the second stage, which may be lower than thetemperature of the liquid layer of the third stage (e.g., the topmoststage in a vertically arranged bubble column). In embodiments relatingto a dehumidifier comprising a plurality of stages (e.g., a multi-stagedehumidifier), the temperature of the liquid layer of the first stagemay be higher than the temperature of the liquid layer of the secondstage, which may be higher than the temperature of the liquid layer ofthe third stage.

The presence of multiple stages within a bubble column humidifier and/orbubble column dehumidifier may, in some cases, advantageously result inincreased humidification and/or dehumidification of a gas. In somecases, the presence of multiple stages may advantageously lead to higherrecovery of substantially pure water. For example, the presence ofmultiple stages may provide numerous locations where the gas may behumidified and/or dehumidified (e.g., treated to recover substantiallypure water). That is, the gas may travel through more than one liquidlayer in which at least a portion of the gas undergoes humidification(e.g., evaporation) or dehumidification (e.g., condensation). Inaddition, the presence of multiple stages may increase the difference intemperature between a liquid stream at an inlet and an outlet of ahumidifier and/or dehumidifier. This may be advantageous in systemswhere heat from a liquid stream (e.g., dehumidifier liquid outletstream) is transferred to a separate stream (e.g., humidifier inputstream) within the system. In such cases, the ability to produce aheated dehumidifier liquid outlet stream can increase the energyeffectiveness of the system. Additionally, the presence of multiplestages may enable greater flexibility for fluid flow within anapparatus. For example, extraction and/or injection of fluids (e.g., gasstreams) from intermediate humidification and/or dehumidification stagesmay occur through intermediate exchange conduits.

In some cases, a bubble column humidifier and/or a bubble columndehumidifier is configured to extract partially humidified gas from atleast one intermediate location in the humidifier (e.g., not the finalhumidification stage) and to inject the partially humidified gas into atleast one intermediate location in the dehumidifier (e.g., not the firstdehumidification stage). In some embodiments, extraction from at leastone intermediate location in the humidifier and injection into at leastone intermediate location in the dehumidifier may be thermodynamicallyadvantageous. Because the portion of the gas flow exiting the humidifierat an intermediate outlet (e.g., the extracted portion) has not passedthrough the entire humidifier, the temperature of the gas flow at theintermediate outlet may be lower than the temperature of the gas flow atthe main gas outlet of the humidifier. The location of the extractionpoints (e.g., outlets) and/or injection points (e.g., inlets) may beselected to increase the thermal efficiency of the system. For example,because a gas (e.g., air) may have increased vapor content at highertemperatures than at lower temperatures, and because the heat capacityof a gas with higher vapor content may be higher than the heat capacityof a gas with lower vapor content, less gas may be used in highertemperature areas of the humidifier and/or dehumidifier to betterbalance the heat capacity rate ratios of the gas (e.g., air) and liquid(e.g., water) streams. Extraction and/or injection at intermediatelocations may therefore advantageously allow for manipulation of gasmass flows and for greater heat recovery.

The humidifier and/or dehumidifier may be of any size. In some cases,the size of the humidifier and/or dehumidifier will generally dependupon the number of humidifiers and/or dehumidifiers employed in thesystem and the total flow rate of the liquid that is to be desalinated.In certain embodiments, the total of the volumes of the humidifiersand/or dehumidifiers used in the system for producing a concentratedbrine stream can be at least about 1 gallon, at least about 10 gallons,at least about 100 gallons, at least about 500 gallons, at least about1,000 gallons, at least about 2,000 gallons, at least about 5,000gallons, at least about 7,000 gallons, at least about 10,000 gallons, atleast about 20,000 gallons, at least about 50,000 gallons, or at leastabout 100,000 gallons (and/or, in some embodiments, up to about1,000,000 gallons, or more).

It should be recognized that the inventive systems and methods describedherein are not limited to those including a bubble column humidifierand/or a bubble column dehumidifier and that other types of humidifiersand/or dehumidifiers may be used in some embodiments. For example, insome embodiments, the humidifier is a packed bed humidifier. In certaincases, the humidifier comprises a packing material (e.g., polyvinylchloride (PVC) packing material). The packing material may, in somecases, facilitate turbulent gas flow and/or enhanced direct contactbetween the liquid stream comprising water and at least one dissolvedsalt and the carrier gas stream within the humidifier. In certainembodiments, the humidifier further comprises a device configured toproduce droplets of the liquid feed stream. For example, a nozzle orother spraying device may be positioned at the top of the humidifiersuch that the liquid feed stream is sprayed downward to the bottom ofthe humidifier. The use of a spraying device can advantageously increasethe degree of contact between the liquid feed stream fed to thehumidifier and the carrier gas stream into which water from the liquidfeed stream is transported.

In some embodiments, an HDH desalination unit further comprises one ormore additional devices. According to some embodiments, for example, anHDH desalination unit further comprises a heat exchanger in fluidcommunication with the humidifier and/or dehumidifier. In certain cases,the heat exchanger advantageously facilitates transfer of heat from aliquid stream exiting the dehumidifier to a liquid stream entering thehumidifier. For example, the heat exchanger may advantageously allowenergy to be recovered from a dehumidifier liquid outlet stream and usedto pre-heat a humidifier liquid inlet stream prior to entry of thehumidifier liquid inlet stream into the humidifier.

In certain embodiments, an HDH desalination unit further comprises anoptional heating device arranged in fluid communication with thehumidifier. The optional heating device may be any device capable oftransferring heat to a liquid stream. The heating device may be a heatexchanger, a heat collection device (e.g., a device configured to storeand/or utilize thermal energy), or an electric heater. In certain cases,the heating device may be arranged such that a liquid feed stream isheated prior to entering the humidifier. Heating the liquid feed streammay, in some cases, increase the degree to which water is transferredfrom the liquid feed stream to the carrier gas stream within thehumidifier.

In some embodiments, an HDH desalination unit further comprises anoptional cooling device arranged in fluid communication with thedehumidifier. In certain cases, a stream comprising substantially purewater may be cooled by the cooling device prior to entering thedehumidifier. A cooling device generally refers to any device that iscapable of removing heat from a fluid stream (e.g., a liquid stream, agas stream). The cooling device may be a heat exchanger (e.g., anair-cooled heat exchanger), a dry cooler, a chiller, a radiator, or anyother device capable of removing heat from a fluid stream.

It should be understood that the inventive systems and methods describedherein are not limited to those including ahumidification-dehumidification desalination unit and that in otherembodiments, other types of desalination units may be employed.Non-limiting examples of suitable desalination units include amechanical vapor compression unit, a multi-effect distillation unit, amulti-stage flash unit, and a vacuum distillation unit. In someembodiments, a desalination system comprises a plurality of desalinationunits, each of which may be any type of desalination unit. Thedesalination units of a desalination system may be the same or differenttypes of desalination units.

In some embodiments, a desalination system used in systems and methodsdescribed herein may have a relatively high liquid feed rate (e.g.,amount of liquid feed entering the system per unit time). In certainembodiments, the desalination system has a liquid feed rate of at leastabout 5 barrels/day, at least about 10 barrels/day, at least about 20barrels/day, at least about 50 barrels/day, at least about 100barrels/day, at least about 200 barrels/day, at least about 300barrels/day, at least about 400 barrels/day, at least about 500barrels/day, at least about 600 barrels/day, at least about 700barrels/day, at least about 800 barrels/day, at least about 900barrels/day, at least about 1,000 barrels a day, at least about 2,000barrels/day, at least about 5,000 barrels/day, at least about 10,000barrels/day, at least about 20,000 barrels/day, at least about 30,000barrels/day, at least about 35,000 barrels/day, at least about 40,000barrels/day, at least about 50,000 barrels/day (and/or, in someembodiments, up to about 100,000 barrels/day, or more).

In some embodiments, the desalination system has a relatively highproduction rate (e.g., amount of substantially pure water produced perunit time). In certain cases, the desalination system has a productionrate of at least about 10 barrels/day, at least about 50 barrels/day, atleast about 100 barrels/day, at least about 200 barrels/day, at leastabout 300 barrels/day, at least about 400 barrels/day, at least about500 barrels/day, at least about 600 barrels/day, at least about 700barrels/day, at least about 800 barrels/day, at least about 900barrels/day, at least about 1,000 barrels a day, at least about 2,000barrels/day, at least about 5,000 barrels/day, or at least about 10,000barrels/day (and/or, in some embodiments, up to about 100,000barrels/day, or more).

Certain of the systems described herein can be configured to desalinatesaline solutions entering at relatively high flow rates, andaccordingly, can be configured to produce relative pure water streams atrelatively high flow rates. For example, in some embodiments, thesystems and methods described herein may be configured and sized tooperate to receive a liquid feed stream at a flow rate of at least about1 gallon/minute, at least about 10 gallons/minute, at least about 100gallons/minute, or at least about 1000 gallons/minute (and/or, incertain embodiments, up to about 10,000 gallons/minute, or more).

In some embodiments, at least a portion of the desalination system(e.g., the dehumidifier of an HDH desalination unit) is configured toproduce a stream comprising water of relatively high purity. Forexample, in some embodiments, the desalination system produces a streamcomprising water in an amount of at least about 95 wt %, at least about99 wt %, at least about 99.9 wt %, or at least about 99.99 wt % (and/or,in certain embodiments, up to about 99.999 wt %, or more). In someembodiments, the percentage volume of a liquid feed stream that isrecovered as fresh water is at least about 40%, at least about 45%, atleast about 50%, at least about 55%, at least about 58%, at least about60%, or at least about 70%.

In some embodiments, the substantially pure water stream has arelatively low concentration of one or more dissolved salts. In somecases, the concentration of at least one dissolved salt (e.g., NaCl) inthe substantially pure water stream is about 500 mg/L or less, about 200mg/L or less, about 100 mg/L or less, about 50 mg/L or less, about 20mg/L or less, about 10 mg/L or less, about 5 mg/L or less, about 2 mg/Lor less, about 1 mg/L or less, about 0.5 mg/L or less, about 0.2 mg/L orless, about 0.1 mg/L or less, about 0.05 mg/L or less, about 0.02 mg/Lor less, or about 0.01 mg/L or less. According to some embodiments, theconcentration of at least one dissolved salt in the substantially purewater stream is substantially zero (e.g., not detectable). In certaincases, the concentration of at least one dissolved salt in thesubstantially pure water stream is in the range of about 0 mg/L to about500 mg/L, about 0 mg/L to about 200 mg/L, about 0 mg/L to about 100mg/L, about 0 mg/L to about 50 mg/L, about 0 mg/L to about 20 mg/L,about 0 mg/L to about 10 mg/L, about 0 mg/L to about 5 mg/L, about 0mg/L to about 2 mg/L, about 0 mg/L to about 1 mg/L, about 0 mg/L toabout 0.5 mg/L, about 0 mg/L to about 0.1 mg/L, about 0 mg/L to about0.05 mg/L, about 0 mg/L to about 0.02 mg/L, or about 0 mg/L to about0.01 mg/L.

In some embodiments, the substantially pure water stream contains atleast one dissolved salt in an amount of about 2 wt % or less, about 1wt % or less, about 0.5 wt % or less, about 0.2 wt % or less, about 0.1wt % or less, about 0.05 wt % or less, or about 0.01 wt % or less. Insome embodiments, the substantially pure water stream contains at leastone dissolved salt in an amount in the range of about 0.01 wt % to about2 wt %, about 0.01 wt % to about 1 wt %, about 0.01 wt % to about 0.5 wt%, about 0.01 wt % to about 0.2 wt %, or about 0.01 wt % to about 0.1 wt%.

In some embodiments, the concentration of at least one dissolved salt inthe substantially pure water stream is substantially less than theconcentration of the at least one dissolved salt in the liquid feedstream received by the desalination system. In some cases, theconcentration of at least one dissolved salt in the substantially purewater stream is at least about 0.5%, about 1%, about 2%, about 5%, about10%, about 15%, or about 20% less than the concentration of the at leastone dissolved salt in the liquid feed stream.

In some embodiments, the substantially pure water stream has arelatively low total dissolved salt concentration. In some cases, thetotal dissolved salt concentration in the substantially pure waterstream is about 500 mg/L or less, about 200 mg/L or less, about 100 mg/Lor less, about 50 mg/L or less, about 20 mg/L or less, about 10 mg/L orless, about 5 mg/L or less, about 2 mg/L or less, about 1 mg/L or less,about 0.5 mg/L or less, about 0.2 mg/L or less, about 0.1 mg/L or less,about 0.05 mg/L or less, about 0.02 mg/L or less, or about 0.01 mg/L orless. According to some embodiments, the total dissolved saltconcentration in the substantially pure water stream is substantiallyzero (e.g., not detectable). In certain embodiments, the total dissolvedsalt concentration in the substantially pure water stream is in therange of about 0 mg/L to about 500 mg/L, about 0 mg/L to about 200 mg/L,about 0 mg/L to about 100 mg/L, about 0 mg/L to about 50 mg/L, about 0mg/L to about 20 mg/L, about 0 mg/L to about 10 mg/L, about 0 mg/L toabout 5 mg/L, about 0 mg/L to about 2 mg/L, about 0 mg/L to about 1mg/L, about 0 mg/L to about 0.5 mg/L, about 0 mg/L to about 0.2 mg/L,about 0 mg/L to about 0.1 mg/L, about 0 mg/L to about 0.05 mg/L, about 0mg/L to about 0.02 mg/L, or about 0 mg/L to about 0.01 mg/L.

In some embodiments, the total dissolved salt concentration of thesubstantially pure water stream is substantially less than the totaldissolved salt concentration of a liquid feed stream received by thedesalination system. In some cases, the total dissolved saltconcentration of the substantially pure water stream is at least about0.5%, about 1%, about 2%, about 5%, about 10%, about 15%, or about 20%less than the total dissolved salt concentration of the liquid feedstream.

According to some embodiments, the substantially pure water stream has arelatively low salinity (e.g., weight percent of all dissolved salts).In some embodiments, the substantially pure water stream has a salinityof about 5% or less, about 2% or less, about 1% or less, about 0.5% orless, about 0.2% or less, about 0.1% or less, about 0.05% or less, orabout 0.01% or less. In some embodiments, the substantially pure waterstream has a salinity in the range of about 0.01% to about 5%, about0.01% to about 2%, about 0.01% to about 1%, about 0.01% to about 0.5%,about 0.01% to about 0.2%, or about 0.01% to about 0.1%.

According to some embodiments, at least a portion of the desalinationsystem (e.g., the humidifier of an HDH desalination unit) is configuredto produce a concentrated brine stream (e.g., a stream comprising arelatively high concentration of at least one dissolved salt). Theconcentrated brine stream may be recirculated through a fluidic circuitcomprising at least a portion of the desalination system until a certaincondition (e.g., a target density and/or salinity) is met. In someembodiments, the recirculated concentrated brine stream may bedischarged upon satisfaction of the condition. The dischargedconcentrated brine stream may, in some cases, have a relatively highsalinity (e.g., wt % of all dissolved salts). In some cases, thesalinity of the discharged concentrated brine stream is at least about10%, at least about 15%, at least about 20%, at least about 25%, atleast about 26%, at least about 27%, at least about 28%, at least about29%, or at least about 30%. In some embodiments, the salinity of thedischarged concentrated brine stream is in the range of about 10% toabout 20%, about 10% to about 25%, about 10% to about 26%, about 10% toabout 27%, about 10% to about 28%, about 10% to about 29%, about 10% toabout 30%, about 15% to about 20%, about 15% to about 25%, about 15% toabout 26%, about 15% to about 27%, about 15% to about 28%, about 15% toabout 29%, about 15% to about 30%, about 20% to about 25%, about 20% toabout 26%, about 20% to about 27%, about 20% to about 28%, about 20% toabout 29%, about 20% to about 30%, about 25 wt % to about 26 wt %, about25 wt % to about 27 wt %, about 25 wt % to about 28 wt %, about 25 wt %to about 29 wt %, or about 25% to about 30%.

The discharged concentrated brine stream may, in some cases, have arelatively high concentration of at least one dissolved salt (e.g.,NaCl). In certain cases, the concentration of at least one dissolvedsalt in the discharged concentrated brine stream is at least about 100mg/L, at least about 200 mg/L, at least about 500 mg/L, at least about1,000 mg/L, at least about 2,000 mg/L, at least about 5,000 mg/L, atleast about 10,000 mg/L, at least about 20,000 mg/L, at least about50,000 mg/L, at least about 75,000 mg/L, at least about 100,000 mg/L, atleast about 150,000 mg/L, at least about 200,000 mg/L, at least about250,000 mg/L, at least about 300,000 mg/L, at least about 350,000 mg/L,at least about 400,000 mg/L, at least about 450,000 mg/L, or at leastabout 500,000 mg/L (and/or, in certain embodiments, up to the solubilitylimit of the salt in the liquid stream). In some embodiments, theconcentration of at least one dissolved salt in the dischargedconcentrated brine stream is in the range of about 1,000 mg/L to about10,000 mg/L, about 1,000 mg/L to about 20,000 mg/L, about 1,000 mg/L toabout 50,000 mg/L, about 1,000 mg/L to about 100,000 mg/L, about 1,000mg/L to about 150,000 mg/L, about 1,000 mg/L to about 200,000 mg/L,about 1,000 mg/L to about 250,000 mg/L, about 1,000 mg/L to about300,000 mg/L, about 1,000 mg/L to about 350,000 mg/L, about 1,000 mg/Lto about 400,000 mg/L, about 1,000 mg/L to about 450,000 mg/L, about1,000 mg/L to about 500,000 mg/L, about 10,000 mg/L to about 20,000mg/L, about 10,000 mg/L to about 50,000 mg/L, about 10,000 mg/L to about100,000 mg/L, about 10,000 mg/L to about 150,000 mg/L, about 10,000 mg/Lto about 200,000 mg/L, about 10,000 mg/L to about 250,000 mg/L, about10,000 mg/L to about 300,000 mg/L, about 10,000 mg/L to about 350,000mg/L, about 10,000 mg/L to about 400,000 mg/L, about 10,000 mg/L toabout 450,000 mg/L, about 10,000 mg/L to about 500,000 mg/L, about20,000 mg/L to about 50,000 mg/L, about 20,000 mg/L to about 100,000mg/L, about 20,000 mg/L to about 150,000 mg/L, about 20,000 mg/L toabout 200,000 mg/L, about 20,000 mg/L to about 250,000 mg/L, about20,000 mg/L to about 300,000 mg/L, about 20,000 mg/L to about 350,000mg/L, about 20,000 mg/L to about 400,000 mg/L, about 20,000 mg/L toabout 450,000 mg/L, about 20,000 mg/L to about 500,000 mg/L, about50,000 mg/L to about 100,000 mg/L, about 50,000 mg/L to about 150,000mg/L, about 50,000 mg/L to about 200,000 mg/L, about 50,000 mg/L toabout 250,000 mg/L, about 50,000 mg/L to about 300,000 mg/L, about50,000 mg/L to about 350,000 mg/L, about 50,000 mg/L to about 400,000mg/L, about 50,000 mg/L to about 450,000 mg/L, about 50,000 mg/L toabout 500,000 mg/L, about 100,000 mg/L to about 150,000 mg/L, about100,000 mg/L to about 200,000 mg/L, about 100,000 mg/L to about 250,000mg/L, about 100,000 mg/L to about 300,000 mg/L, about 100,000 mg/L toabout 350,000 mg/L, about 100,000 mg/L to about 400,000 mg/L, about100,000 mg/L to about 450,000 mg/L, or about 100,000 mg/L to about500,000 mg/L.

In some embodiments, the discharged concentrated brine stream containsat least one dissolved salt (e.g., NaCl) in an amount of at least about1 wt %, at least about 5 wt %, at least about 10 wt %, at least about 15wt %, at least about 20 wt %, at least about 25 wt %, at least about 26wt %, at least about 27 wt %, at least about 28 wt %, at least about 29wt %, or at least about 30 wt % (and/or, in certain embodiments, up tothe solubility limit of the salt in the liquid stream). In someembodiments, the discharged concentrated brine stream comprises at leastone dissolved salt in an amount in the range of about 1 wt % to about 10wt %, about 1 wt % to about 20 wt %, about 1 wt % to about 25 wt %,about 1 wt % to about 26 wt %, about 1 wt % to about 27 wt %, about 1 wt% to about 28 wt %, about 1 wt % to about 29 wt %, about 1 wt % to about30 wt %, about 10 wt % to about 20 wt %, about 10 wt % to about 25 wt %,about 10 wt % to about 26 wt %, about 10 wt % to about 27 wt %, about 10wt % to about 28 wt %, about 10 wt % to about 29 wt %, about 10 wt % toabout 30 wt %, about 20 wt % to about 25 wt %, about 20 wt % to about 26wt %, about 20 wt % to about 27 wt %, about 20 wt % to about 28 wt %,about 20 wt % to about 29 wt %, about 20 wt % to about 30 wt %, about 25wt % to about 26 wt %, about 25 wt % to about 27 wt %, about 25 wt % toabout 28 wt %, about 25 wt % to about 29 wt %, or about 25 wt % to about30 wt %.

In some embodiments, the concentration of at least one dissolved salt inthe concentrated brine stream is substantially greater than theconcentration of the at least one dissolved salt in the liquid feedstream received by the desalination system. In some cases, theconcentration of at least one dissolved salt in the concentrated brinestream is at least about 0.5%, about 1%, about 2%, about 5%, about 10%,about 15%, or about 20% greater than the concentration of the at leastone dissolved salt in the liquid feed stream.

In some embodiments, the total dissolved salt concentration of theconcentrated brine stream upon discharge may be relatively high. Incertain cases, the total dissolved salt concentration of the dischargedconcentrated brine stream is at least about 1,000 mg/L, at least about2,000 mg/L, at least about 5,000 mg/L, at least about 10,000 mg/L, atleast about 20,000 mg/L, at least about 50,000 mg/L, at least about75,000 mg/L, at least about 100,000 mg/L, at least about 150,000 mg/L,at least about 200,000 mg/L, at least about 250,000 mg/L, at least about300,000 mg/L, at least about 350,000 mg/L, at least about 400,000 mg/L,at least about 450,000 mg/L, at least about 500,000 mg/L, at least about550,000 mg/L, or at least about 600,000 mg/L (and/or, in certainembodiments, up to the solubility limit of the salt(s) in theconcentrated brine stream). In some embodiments, the total saltconcentration of the discharged concentrated brine stream is in therange of about 10,000 mg/L to about 20,000 mg/L, about 10,000 mg/L toabout 50,000 mg/L, about 10,000 mg/L to about 100,000 mg/L, about 10,000mg/L to about 150,000 mg/L, about 10,000 mg/L to about 200,000 mg/L,about 10,000 mg/L to about 250,000 mg/L, about 10,000 mg/L to about300,000 mg/L, about 10,000 mg/L to about 350,000 mg/L, about 10,000 mg/Lto about 400,000 mg/L, about 10,000 mg/L to about 450,000 mg/L, about10,000 mg/L to about 500,000 mg/L, about 10,000 mg/L to about 550,000mg/L, about 10,000 mg/L to about 600,000 mg/L, about 20,000 mg/L toabout 50,000 mg/L, about 20,000 mg/L to about 100,000 mg/L, about 20,000mg/L to about 150,000 mg/L, about 20,000 mg/L to about 200,000 mg/L,about 20,000 mg/L to about 250,000 mg/L, about 20,000 mg/L to about300,000 mg/L, about 20,000 mg/L to about 350,000 mg/L, about 20,000 mg/Lto about 400,000 mg/L, about 20,000 mg/L to about 450,000 mg/L, about20,000 mg/L to about 500,000 mg/L, about 20,000 mg/L to about 550,000mg/L, about 20,000 mg/L to about 600,000 mg/L, about 50,000 mg/L toabout 100,000 mg/L, about 50,000 mg/L to about 150,000 mg/L, about50,000 mg/L to about 200,000 mg/L, about 50,000 mg/L to about 250,000mg/L, about 50,000 mg/L to about 300,000 mg/L, about 50,000 mg/L toabout 350,000 mg/L, about 50,000 mg/L to about 400,000 mg/L, about50,000 mg/L to about 450,000 mg/L, about 50,000 mg/L to about 500,000mg/L, about 50,000 mg/L to about 550,000 mg/L, about 50,000 mg/L toabout 600,000 mg/L, about 100,000 mg/L to about 200,000 mg/L, about100,000 mg/L to about 250,000 mg/L, about 100,000 mg/L to about 300,000mg/L, about 100,000 mg/L to about 350,000 mg/L, about 100,000 mg/L toabout 400,000 mg/L, about 100,000 mg/L to about 450,000 mg/L, about100,000 mg/L to about 500,000 mg/L, about 100,000 mg/L to about 550,000mg/L, or about 100,000 mg/L to about 600,000 mg/L.

In some embodiments, the total dissolved salt concentration of thedischarged concentrated brine stream is significantly higher than thetotal dissolved salt concentration of a liquid feed stream received bythe desalination system. In some cases, the total dissolved saltconcentration of the discharged concentrated brine stream is at leastabout 5%, at least about 6%, at least about 10%, at least about 14%, atleast about 15%, at least about 20%, or at least about 25% greater thanthe total dissolved salt concentration of the liquid feed stream.

In some cases, the concentration of at least one salt in theconcentrated brine stream is at or near the saturation limit. Thesaturation limit of an aqueous saline solution, as used herein, refersto the concentration of a salt at which 0.5 wt % of the aqueous solutionis made up of the salt. The above-defined saturation limit is typicallyat or near the bulk salt concentration at which there is inception ofcrystal formation. One can determine whether a given solution is at itssaturation limit with respect to the salt(s) contained within theaqueous solution by inspecting the solution to determine whether theformation of solid salt is occurring. In some cases, a concentratedbrine comprising at least one salt at or near the saturation limit maybe referred to as a “saturated brine.”

Generally, the saturation limit of an aqueous saline solution willdepend upon the temperature, pressure, and flow velocity of the salinesolution. For example, saline aqueous solutions at relatively hightemperatures will generally have higher solubility limits than salineaqueous solutions at relatively low temperatures. As another example,saline aqueous solutions at relatively high flow velocities willgenerally have higher solubility limits than saline aqueous solutions atrelatively low flow velocities.

According to some embodiments, the discharged concentrated brine streamhas a relatively high density. It may be advantageous, in some cases,for a concentrated brine stream to have a relatively high density, as ahigher density may result in increased effectiveness in certainapplications (e.g., use as a kill fluid for oil or gas wells). In somecases, the density of the discharged concentrated brine stream ismeasured at a temperature of about 120° F. or less, about 100° F. orless, about 80° F. or less, about 72° F. or less, about 60° F. or less,or about 40° F. or less. In some embodiments, the density of thedischarged concentrated brine stream is measured at a temperature of atleast about 40° F., at least about 60° F., at least about 72° F., atleast about 80° F., at least about 100° F., or at least about 120° F. Insome embodiments, the density of the discharged concentrated brinestream is measured at a temperature in the range of about 40° F. toabout 120° F., about 40° F. to about 100° F., about 40° F. to about 80°F., about 40° F. to about 72° F., about 40° F. to about 60° F., about60° F. to about 120° F., about 60° F. to about 100° F., or about 60° F.to about 80° F. In certain embodiments, the discharged concentratedbrine stream has a density (e.g., measured at about 60° F.) of at leastabout 9.5 pounds/gallon, at least about 10 pounds/gallon, at least about10.5 pounds/gallon, at least about 11 pounds/gallon, at least about 11.5pounds/gallon, at least about 12 pounds/gallon, or at least about 15pounds/gallon. In some embodiments, the discharged concentrated brinestream (e.g., measured at about 60° F.) has a density in the range ofabout 10 pounds/gallon to about 11 pounds/gallon, about 10 pounds/gallonto about 11.5 pounds/gallon, about 10 pounds/gallon to about 12pounds/gallon, about 10 pounds/gallon to about 15 pounds/gallon, about11 pounds/gallon to about 11.5 pounds/gallon, about 11 pounds/gallon toabout 12 pounds/gallon, about 11 pounds/gallon to about 15pounds/gallon, or about 11.5 pounds/gallon to about 15 pounds/gallon.

In some embodiments, a system for producing a concentrated brine streamcomprises one or more tanks. For example, a system may comprise one ormore feed tanks and/or one or more concentrated brine storage tanks. Thetanks may be any type of tank known in the art and may comprise anyvessel capable of holding a volume of a liquid. The tanks may also haveany size. In some cases, the tanks may be relatively large. According tocertain embodiments, one or more tanks in a system for producing aconcentrated brine stream have a volume of at least about 1,000 gallons,at least about 2,000 gallons, at least about 5,000 gallons, at leastabout 7,000 gallons, at least about 10,000 gallons, at least about20,000 gallons, or at least about 50,000 gallons.

In some embodiments, a system for producing a concentrated brine streamis configured to recover heat from concentrated brine streams that aredischarged from the system. During the transient operation of adesalination system, a concentrated brine stream recirculating throughthe system may be heated to a relatively high temperature. It may beadvantageous to recover at least a portion of the heat of therecirculated concentrated brine stream prior to discharging therecirculated concentrated brine stream from the system instead ofwasting the thermal energy. Accordingly, in some embodiments, the systemcomprises at least one heat exchanger. Prior to being discharged fromthe system, a recirculated concentrated brine stream may flow through afirst portion of the heat exchanger. While the recirculated concentratedbrine stream is flowing through a first portion of the heat exchanger,an incoming liquid feed stream may flow through a second portion of theheat exchanger, and heat may be transferred from the recirculatedconcentrated brine stream to the liquid feed stream. In some cases, itmay be desirable for the liquid feed stream to be at a relatively hightemperature in order to promote evaporation of water vapor from theliquid feed stream to a carrier gas stream in the humidifier. Recoveryof heat from the recirculated concentrated brine stream may avoid theneed to use an external heating device to heat the liquid feed stream ormay reduce the amount of external input energy needed to heat the liquidfeed stream prior to flowing through the humidifier. In addition, largetemperature differences between the concentrated brine stream flowingthrough a recirculation loop and the incoming liquid feed stream maydisrupt the thermal steady state of the system. A system including oneor more heat exchangers operated to promote energy recovery mayadvantageously reduce the temperature difference between therecirculated concentrated brine stream and the incoming liquid feedstream.

FIG. 3A shows an exemplary schematic diagram of a system 300 forproducing a concentrated brine stream that is configured to recover heatfrom concentrated brine streams discharged from the system. In FIG. 3A,system 300 comprises desalination system 302, first feed tank 304,second feed tank 306, and heat exchanger 308. In addition, system 300comprises a plurality of valves 310, 312, 314, 316, 318, 320, 322, 324,326, and 328, and a plurality of conduits 330, 332, 334, 336, 338, 340,342, 344, 346, 348, 350, 352, and 354.

In operation, a first liquid feed stream comprising water and at leastone dissolved salt may enter system 300. Initially, valves 310 and 314may be open, and the first liquid feed stream may flow through conduit330, heat exchanger 308, and conduit 334 to first feed tank 304. Valves310 and 314 may then be closed, and valves 318 and 322 may be opened.The first liquid feed stream may flow through conduits 338 and 342 todesalination system 302. In desalination system 302, at least a portionof the water may be removed from the first liquid feed stream to producea first concentrated brine stream enriched in the at least one dissolvedsalt relative to the first liquid feed stream. Desalination system 302may also be configured to produce a stream of substantially pure water,at least a portion of which may be discharged from system 300 throughconduit 346. In some embodiments, at least a portion of the stream ofsubstantially pure water is recirculated back to desalination system302.

The first concentrated brine stream may be made to flow through conduits344 and 348 to be returned to first feed tank 304. The firstconcentrated brine stream may continue to be fed to/from first feed tank304 and recirculated through desalination system 302 until a certaincondition (e.g., target density and/or salinity) is met. With eachsuccessive pass through the desalination system, the density and/orsalinity (e.g., concentration of the at least one salt) of the firstconcentrated brine stream may increase. Upon satisfaction of thecondition, valves 318 and 322 may be closed, and valves 312 and 328 maybe opened. The recirculated first concentrated brine stream, which mayhave a relatively high temperature, may flow from first feed tank 304 toheat exchanger 308 through fluid conduit 352. While the recirculatedfirst concentrated brine stream flows through heat exchanger 308, valves310 and 316 may be opened, and a second liquid feed stream comprisingwater and at least one dissolved salt may flow through conduit 330 toheat exchanger 308. In heat exchanger 308, heat may be transferred fromthe recirculated first concentrated brine stream to the second liquidfeed stream. The heated second liquid feed stream may then flow throughconduit 336 to second feed tank 306.

Once second feed tank 306 has been filled, valves 310, 312, 316, and 328may be closed, and valves 320 and 324 may be opened. The heated secondliquid feed stream may then flow through conduits 340 and 342 fromsecond feed tank 306 to desalination system 302. In desalination system302, at least a portion of the water may be removed from the secondliquid feed stream to produce a second concentrated brine stream. Thesecond concentrated brine stream may flow through conduits 344 and 350from desalination system 302 to second feed tank 306. The secondconcentrated brine stream may be fed to/from second feed tank 306 andrecirculated through desalination system 302 until a certain conditionis reached. Upon satisfaction of the condition, valves 320 and 324 maybe closed, and valves 326, 312, 310, and 314 may be opened. Therecirculated second concentrated brine stream may flow through conduit354 to heat exchanger 308. In heat exchanger 308, heat may betransferred from the recirculated second concentrated brine stream to athird liquid feed stream entering system 300 through conduit 330 andheat exchanger 308 and flowing through conduit 334 to first feed tank304. In this manner, heat from a discharged stream (e.g., effluentbrine) may be recovered and transferred to an incoming liquid stream.This alternating operation may be repeated any desired number of times.

According to some embodiments, a system for producing a concentratedbrine stream comprises a heat exchanger. Any heat exchanger known in theart may be used. Examples of suitable heat exchangers include, but arenot limited to, plate-and-frame heat exchangers, shell-and-tube heatexchangers, tube-and-tube heat exchangers, plate heat exchangers,plate-and-shell heat exchangers, spiral heat exchangers, and the like.In a particular embodiment, the heat exchanger is a plate-and-frame heatexchanger. In certain embodiments, the heat exchanger may be configuredsuch that a first fluid stream and a second fluid stream flow throughthe heat exchanger. In some cases, the first fluid stream and the secondfluid stream may flow in substantially the same direction (e.g.,parallel flow), substantially opposite directions (e.g., counter flow),or substantially perpendicular directions (e.g., cross flow). In somecases, more than two fluid streams may flow through the heat exchanger.In an exemplary embodiment, the heat exchanger is a counter-flowplate-and-frame heat exchanger. In some cases, a counter-flowplate-and-frame heat exchanger may advantageously result in a smalltemperature difference between two fluid streams flowing through theheat exchanger.

In some embodiments, a relatively large amount of heat may betransferred between the concentrated brine stream and the incomingliquid stream. For example, the difference between the temperature of afluid entering the heat exchanger and the fluid exiting the heatexchanger may be at least about 5° C., at least about 10° C., at leastabout 15° C., at least about 20° C., at least about 30° C., at leastabout 40° C., at least about 50° C., at least about 60° C., at leastabout 70° C., at least about 80° C., at least about 90° C., or at leastabout 100° C. In some embodiments, the difference between thetemperature of a fluid entering the heat exchanger and the fluid exitingthe heat exchanger may be in the range of about 5° C. to about 20° C.,about 5° C. to about 30° C., about 5° C. to about 50° C., about 5° C. toabout 60° C., about 5° C. to about 90° C., about 5° C. to about 100° C.,about 10° C. to about 30° C., about 10° C. to about 60° C., about 10° C.to about 90° C., about 10° C. to about 100° C., about 20° C. to about60° C., about 20° C. to about 90° C., about 20° C. to about 100° C.,about 30° C. to about 60° C., about 30° C. to about 90° C., about 30° C.to about 100° C., about 50° C. to about 100° C., about 60° C. to about90° C., about 60° C. to about 100° C., or about 80° C. to about 100° C.

In some embodiments, a system for producing a concentrated brine streammay be configured to not only directly recover heat from a concentratedbrine stream being discharged from the system, but also to recoverresidual heat remaining in a tank used to store the concentrated brinestream. In some cases, while a first portion of a concentrated brinestream is recirculating through a desalination system, a second portionof the concentrated brine stream may be circulated from a concentratedbrine storage tank to a heat exchanger. A portion of a liquid feedstream comprising water and at least one dissolved salt may also becirculated from a feed tank to the heat exchanger. An amount of heat maybe transferred from the concentrated brine stream to the liquid feedstream in the heat exchanger. Recovery of heat from a concentrated brinestorage tank during periods between concentrated brine discharges may bereferred to as secondary heat recovery, while direct recovery of heatfrom a discharged concentrated brine stream flowing through a heatexchanger may be referred to as primary heat recovery.

An exemplary schematic diagram of a system for producing a concentratedbrine stream that is configured for secondary heat recovery is shown inFIG. 3B. As shown in FIG. 3B, system 300 comprises desalination system302, feed tank 304, concentrated brine tank 356, and counter-flow heatexchanger 308. System 300 also comprises valves 360 and 370 and conduits330, 332, 358, 362, 364, 366, 368, 372, and 374. In certain embodiments,desalination system 302 comprises a plurality of desalination units. Forexample, in certain cases, desalination system 302 comprises one or moredesalination units connected in parallel.

In operation, a liquid feed stream comprising water and at least onedissolved salt may enter system 300 through conduit 330, flowing intofeed tank 304. Initially, valve 360 may be closed, and the liquid streammay flow from feed tank 304 through conduit 358, heat exchanger 308, andconduits 362 and 364 to desalination system 302. In desalination system302, at least a portion of the water may be removed from the liquid feedstream to produce a concentrated brine stream enriched in the at leastone dissolved salt relative to the liquid feed stream. The concentratedbrine stream may be recirculated through desalination system 302 untilthe concentrated brine stream reaches a certain condition (e.g., atarget density and/or salinity). Upon satisfaction of the condition, therecirculated concentrated brine stream may exit desalination system 302through conduit 368. Valve 370 may be closed, and the recirculatedconcentrated brine stream may flow through heat exchanger 308 in a firstdirection. At the same time, a second liquid feed stream comprisingwater and at least one dissolved salt may flow through heat exchanger308 in a second, substantially opposite direction, and heat may betransferred from the recirculated concentrated brine stream to thesecond liquid feed stream, thereby forming a cooled recirculatedconcentrated brine stream and a heated second liquid feed stream. Theheated second liquid feed stream may flow through conduits 362 and 364to desalination system 302. The cooled concentrated brine stream mayflow through conduit 374 to concentrated brine tank 356. In some cases,at least a portion of the cooled concentrated brine stream may bedischarged from system 300 through conduit 332, and at least a portionof the cooled concentrated brine stream may remain in concentrated brinetank 356.

In some cases, in between discharges of concentrated brine streams fromdesalination system 302, valves 360 and 370 may be opened, and an amountof concentrated brine may be made to flow from concentrated brine tank356 to heat exchanger 308 while an amount of a liquid feed stream ismade to flow from feed tank 304 to heat exchanger 308. Heat may betransferred from the concentrated brine stream to the liquid feedstream, further cooling the concentrated brine stream and heating theliquid feed stream. The cooled concentrated brine stream may be returnedto concentrated brine tank 356 through conduit 374, and the heatedliquid feed stream may be returned to feed tank 304 through conduits 362and 366. In some cases, feed tank 304 and concentrated brine tank 356may reach a thermal equilibrium.

In some embodiments, a parallel flow heat exchanger may be used. Forexample, FIG. 3C shows an exemplary schematic diagram of a system 300for producing a concentrated brine stream that comprises a parallel flowheat exchanger. As shown in FIG. 3C, system 300 comprises desalinationsystem 302 comprising desalination units 302A, 302B, and 302C, inaddition to feed tank 304, concentrated brine tank 356, and heatexchanger 308. According to the embodiment shown in FIG. 3C, heatexchanger 308 is a parallel flow heat exchanger. In some cases, it maybe advantageous to use a parallel flow heat exchanger for secondary heatrecovery, as such a heat exchanger may require less area than acounter-flow heat exchanger. System 300 also comprises conduits 330,332, 376, 378, 380, 382, 384A, 384B, 384C, 386A, 386B, 386C, 388A, 388B,388C, 390, 392, 394, 396, and 398.

In operation, first desalination unit 302A, second desalination unit302B, and third desalination unit 302C may be brought into operationsequentially. In each of the desalination units, a liquid feed streammay be fed to the unit (e.g., through conduit 384A, 384B, or 384C), anda concentrated brine stream and a substantially pure water stream may beproduced. The concentrated brine streams may be recirculated througheach of the desalination units (e.g., through conduit 386A, 386B, or386C) until a certain condition (e.g., a target density and/or salinity)is satisfied. Optionally, a liquid feed stream may be added to thedesalination unit (e.g., through 384A, 384B, or 384C) at the same ratethat the substantially pure water stream is discharged from thedesalination unit in order to maintain a constant volume in each unit.In some cases, the specified condition may first be satisfied indesalination unit 302A, and the recirculated concentrated brine streamfrom desalination unit 302A may be discharged through conduit 388A. Atleast a portion of the concentrated brine stream may flow throughconduits 390 and 394 to heat exchanger 308. A second liquid feed streammay simultaneously flow through heat exchanger 308, and heat may betransferred from the concentrated brine stream to the second liquid feedstream to produce a cooled concentrated brine stream and a heated secondliquid feed stream. The heated second liquid feed stream may flowthrough conduit 380 to return to feed tank 304, and the cooledconcentrated brine stream may flow through conduit 398 to concentratedbrine tank 356. In some cases, the specified condition may subsequentlybe satisfied in desalination unit 302B, and the recirculatedconcentrated brine stream from desalination unit 302B may be dischargedthrough conduit 388B. The specified condition may then be satisfied indesalination unit 302C, and the recirculated concentrated brine streamfrom desalination unit 302C may be discharged through conduit 388C. Inthis manner, amounts of concentrated brine may be discharged fromdesalination units 302A, 302B, and 302C.

In certain cases, in between periods of discharge from one ofdesalination units 302A, 302B, and 302C, a portion of the concentratedbrine stream may flow from concentrated brine tank 356 through conduit396 to heat exchanger 308 while a portion of the second liquid feedstream flows from feed tank 304 to heat exchanger 308 (e.g., throughconduits 376 and 378). In heat exchanger 308, heat may be transferredfrom the concentrated brine stream to the second liquid feed stream. Thecooled concentrated brine stream may then be returned to concentratedbrine tank 356 through conduit 398, and the heated liquid feed streammay be returned to feed tank 304 through conduit 380.

Some aspects are related to a method of forming an ultra-high-densityconcentrated brine stream (e.g., a concentrated brine stream having adensity of at least about 11.7 pounds/gallon). In some embodiments, amethod of forming an ultra-high-density concentrated brine streamcomprises the step of adding an amount of one or more salts to a liquidstream to produce an ultra-high-density concentrated brine stream. Forexample, in certain embodiments, a concentrated brine stream comprisingat least one dissolved salt is produced by a transiently-operateddesalination system according to systems and methods described herein,and an amount of one or more additional salts is added to theconcentrated brine stream to produce an ultra-high-density concentratedbrine stream. In some cases, an amount of one or more salts may be addedto other types of liquid streams, such as a concentrated brine streamproduced by a continuously-operated desalination system, a liquid feedstream (e.g., produced water, flowback water), a stream of substantiallypure water, or any other type of liquid stream. Non-limiting examples ofsuitable salts to add to a concentrated brine stream (e.g., aconcentrated brine stream produced by a transiently-operateddesalination system), a liquid feed stream, a substantially pure waterstream, and/or another liquid stream to produce an ultra-high-densityconcentrated brine stream include sodium chloride (NaCl), calciumchloride (CaCl₂), magnesium chloride (MgCl₂), copper (II) chloride(CuCl₂), iron (III) chloride hexahydrate (FeCl₃.6H₂O), iron (III)chloride (FeCl₃), lithium chloride (LiCl), manganese (II) chloride(MnCl₂), nickel (II) chloride (NiCl₂), zinc chloride (ZnCl₂), sodiumbromide (NaBr), calcium bromide (CaBr₂), magnesium bromide (MgBr₂),potassium bromide (KBr), copper (II) bromide (CuBr₂), iron (III) bromide(FeBr₃), lithium bromide (LiBr), manganese (II) bromide (MnBr₂), nickel(II) bromide (NiBr₂), zinc bromide (ZnBr₂), ammonium nitrate (NH₄NO₃),sodium nitrate (NaNO₃), lithium nitrate (LiNO₃), calcium nitrate(Ca(NO₃)₂), magnesium nitrate (Mg(NO₃)₂), strontium nitrate (Sr(NO₃)₂),calcium nitrate tetrahydrate (Ca(NO₃)₂.4H₂O), copper (II) nitrate(Cu(NO₃)₂), iron (II) nitrate (Fe(NO₃)₂), iron (III) nitrate (Fe(NO₃)₃),nickel (II) nitrate (Ni(NO₃)₂), and/or zinc nitrate (Zn(NO₃)₂). In someembodiments, at least one of the one or more additional salts added to aliquid stream comprising water and at least one dissolved salt isdifferent from the at least one dissolved salt. In some embodiments,each of the one or more additional salts added to the liquid stream isdifferent from the at least one dissolved salt. In certain cases, atleast one of the one or more additional salts added to the liquid streamis the same as the at least one dissolved salt.

In certain cases, an ultra-high-density concentrated brine stream isformed from a substantially solid material. As described in furtherdetail herein, a system for producing a concentrated brine stream maycomprise a desalination system (e.g., a desalination system configuredto be transiently operated) and, optionally, a pretreatment systemand/or precipitation apparatus fluidly connected to the desalinationsystem. In certain embodiments, the pretreatment system and/orprecipitation apparatus may be configured to produce a substantiallysolid material (e.g., a filter cake). In certain cases, thesubstantially solid material comprises calcium carbonate (CaCO₃). Insome cases, a method of forming an ultra-high-density concentrated brinestream comprises the step of adding an amount of one or more acids tothe substantially solid material. Non-limiting examples of suitableacids to add to the substantially solid material include hydrochloricacid (HCl) and nitric acid (HNO₃). According to certain embodiments,addition of hydrochloric acid to a substantially solid materialcomprising calcium carbonate can produce an ultra-high-densityconcentrated brine stream comprising dissolved calcium chloride (CaCl₂).In some cases, addition of hydrochloric acid to the substantially solidmaterial can produce carbon dioxide (CO₂). In certain embodiments, theCO₂ may be collected and advantageously used to increase the alkalinityof a liquid feed stream prior to an ion removal step in a pretreatmentprocess, reducing the amount of soda ash required. In some cases, theCO₂ may be used to decrease the pH of the feed stream prior to a pHadjustment step of the pretreatment process, reducing the amount ofadditional acid (e.g., HCl) required. In some embodiments, addition ofnitric acid to a substantially solid material comprising calciumcarbonate can produce an ultra-high-density concentrated brine streamcomprising dissolved calcium nitrate (Ca(NO₃)₂).

In some embodiments, the ultra-high-density concentrated brine streamhas a density (e.g., measured at about 60° F.) of at least about 11pounds/gallon, at least about 11.5 pounds/gallon, at least about 11.7pounds/gallon, at least about 12 pounds/gallon, at least about 12.5pounds/gallon, at least about 13 pounds/gallon, at least about 13.2pounds/gallon, at least about 13.5 pounds/gallon, at least about 14pounds/gallon, at least about 14.5 pounds/gallon, at least about 15pounds/gallon, at least about 20 pounds/gallon, or at least about 25pounds/gallon. In certain cases, the ultra-high-density concentratedbrine stream has a density (e.g., measured at about 60° F.) in the rangeof about 11 pounds/gallon to about 12 pounds/gallon, about 11pounds/gallon to about 12.5 pounds/gallon, about 11 pounds/gallon toabout 13 pounds/gallon, about 11 pounds/gallon to about 13.2pounds/gallon, about 11 pounds/gallon to about 13.5 pounds/gallon, about11 pounds/gallon to about 14 pounds/gallon, about 11 pounds/gallon toabout 14.5 pounds/gallon, about 11 pounds/gallon to about 15pounds/gallon, about 11 pounds/gallon to about 20 pounds/gallon, about11 pounds/gallon to about 25 pounds/gallon, about 11.5 pounds/gallon toabout 12 pounds/gallon, about 11.5 pounds/gallon to about 12.5pounds/gallon, about 11.5 pounds/gallon to about 13 pounds/gallon, about11.5 pounds/gallon to about 13.2 pounds/gallon, about 11.5 pounds/gallonto about 13.5 pounds/gallon, about 11.5 pounds/gallon to about 14pounds/gallon, about 11.5 pounds/gallon to about 14.5 pounds/gallon,about 11.5 pounds/gallon to about 15 pounds/gallon, about 11.5pounds/gallon to about 20 pounds/gallon, about 11.5 pounds/gallon toabout 25 pounds/gallon, about 11.7 pounds/gallon to about 12.5pounds/gallon, about 11.7 pounds/gallon to about 13 pounds/gallon, about11.7 pounds/gallon to about 13.2 pounds/gallon, about 11.7 pounds/gallonto about 13.5 pounds/gallon, about 11.7 pounds/gallon to about 14pounds/gallon, about 11.7 pounds/gallon to about 14.5 pounds/gallon,about 11.7 pounds/gallon to about 15 pounds/gallon, about 11.7pounds/gallon to about 20 pounds/gallon, about 11.7 pounds/gallon toabout 25 pounds/gallon, about 12 pounds/gallon to about 12.5pounds/gallon, about 12 pounds/gallon to about 13 pounds/gallon, about12 pounds/gallon to about 13.2 pounds/gallon, about 12 pounds/gallon toabout 13.5 pounds/gallon, about 12 pounds/gallon to about 14pounds/gallon, about 12 pounds/gallon to about 14.5 pounds/gallon, about12 pounds/gallon to about 15 pounds/gallon, about 12 pounds/gallon toabout 20 pounds/gallon, about 12 pounds/gallon to about 25pounds/gallon, about 12.5 pounds/gallon to about 13 pounds/gallon, about12.5 pounds/gallon to about 13.2 pounds/gallon, about 12.5 pounds/gallonto about 13.5 pounds/gallon, about 12.5 pounds/gallon to about 14pounds/gallon, about 12.5 pounds/gallon to about 14.5 pounds/gallon,about 12.5 pounds/gallon to about 15 pounds/gallon, about 12.5pounds/gallon to about 20 pounds/gallon, about 12.5 pounds/gallon toabout 25 pounds/gallon, about 13 pounds/gallon to about 13.2pounds/gallon, about 13 pounds/gallon to about 13.5 pounds/gallon, about13 pounds/gallon to about 14 pounds/gallon, about 13 pounds/gallon toabout 14.5 pounds/gallon, about 13 pounds/gallon to about 15pounds/gallon, about 13 pounds/gallon to about 20 pounds/gallon, about13 pounds/gallon to about 25 pounds/gallon, about 13.5 pounds/gallon toabout 14 pounds/gallon, about 13.5 pounds/gallon to about 14.5pounds/gallon, about 13.5 pounds/gallon to about 15 pounds/gallon, about13.5 pounds/gallon to about 20 pounds/gallon, about 13.5 pounds/gallonto about 25 pounds/gallon, about 14 pounds/gallon to about 15pounds/gallon, about 14 pounds/gallon to about 20 pounds/gallon, about14 pounds/gallon to about 25 pounds/gallon, about 15 pounds/gallon toabout 20 pounds/gallon, about 15 pounds/gallon to about 25pounds/gallon, or about 20 pounds/gallon to about 25 pounds/gallon. Insome cases, the density of the ultra-high-density concentrated brinestream is measured at a temperature of about 120° F. or less, about 100°F. or less, about 80° F. or less, about 72° F. or less, about 68° F. orless, about 60° F. or less, about 50° F. or less, or about 40° F. orless. In some embodiments, the density of the ultra-high-densityconcentrated brine stream is measured at a temperature of at least about40° F., at least about 50° F., at least about 60° F., at least about 68°F., at least about 72° F., at least about 80° F., at least about 100°F., or at least about 120° F. In some embodiments, the density of theultra-high-density concentrated brine stream is measured at atemperature in the range of about 40° F. to about 120° F., about 40° F.to about 100° F., about 40° F. to about 80° F., about 40° F. to about72° F., about 40° F. to about 68° F., about 40° F. to about 60° F.,about 40° F. to about 50° F., about 60° F. to about 120° F., about 60°F. to about 100° F., about 60° F. to about 80° F., about 60° F. to about72° F., or about 60° F. to about 68° F.

In some cases, the concentration of at least one dissolved salt (e.g.,NaCl) in the ultra-high-density concentrated brine stream is relativelyhigh. In certain cases, the concentration of at least one dissolved saltin the ultra-high-density concentrated brine stream is at least about10,000 mg/L, at least about 20,000 mg/L, at least about 50,000 mg/L, atleast about 80,000 mg/L, at least about 85,000 mg/L, at least about90,000 mg/L, at least about 100,000 mg/L, at least about 150,000 mg/L,at least about 180,000 mg/L, at least about 200,000 mg/L, at least about250,000 mg/L, at least about 270,000 mg/L, at least about 300,000 mg/L,at least about 350,000 mg/L, at least about 380,000 mg/L, at least about400,000 mg/L, at least about 450,000 mg/L, at least about 480,000 mg/L,at least about 500,000 mg/L, at least about 600,000 mg/L, at least about700,000 mg/L, at least about 800,000 mg/L, at least about 900,000 mg/L,at least about 1,000,000 mg/L, or at least about 1,100,000 mg/L (and/or,in certain embodiments, up to the solubility limit of the salt in theliquid stream). In some embodiments, the concentration of at least onedissolved salt in the ultra-high-density concentrated brine stream is inthe range of about 10,000 mg/L to about 500,000 mg/L, about 20,000 mg/Lto about 500,000 mg/L, about 50,000 mg/L to about 500,000 mg/L, about80,000 mg/L to about 500,000 mg/L, about 85,000 mg/L to about 500,000mg/L, about 90,000 mg/L to about 500,000 mg/L, about 100,000 mg/L toabout 500,000 mg/L, about 150,000 mg/L to about 500,000 mg/L, about180,000 mg/L to about 500,000 mg/L, about 200,000 mg/L to about 500,000mg/L, about 250,000 mg/L to about 500,000 mg/L, about 280,000 mg/L toabout 500,000 mg/L, about 300,000 mg/L to about 500,000 mg/L, about350,000 mg/L to about 500,000 mg/L, about 380,000 mg/L to about 500,000mg/L, about 400,000 mg/L to about 500,000 mg/L, or about 450,000 mg/L toabout 500,000 mg/L, about 10,000 mg/L to about 1,100,000 mg/L, about20,000 mg/L to about 1,100,000 mg/L, about 50,000 mg/L to about1,100,000 mg/L, about 80,000 mg/L to about 1,100,000 mg/L, about 85,000mg/L to about 1,100,000 mg/L, about 90,000 mg/L to about 1,100,000 mg/L,about 100,000 mg/L to about 1,100,000 mg/L, about 150,000 mg/L to about1,100,000 mg/L, about 180,000 mg/L to about 1,100,000 mg/L, about200,000 mg/L to about 1,100,000 mg/L, about 250,000 mg/L to about1,100,000 mg/L, about 280,000 mg/L to about 1,100,000 mg/L, about300,000 mg/L to about 1,100,000 mg/L, about 350,000 mg/L to about1,100,000 mg/L, about 380,000 mg/L to about 1,100,000 mg/L, about400,000 mg/L to about 1,100,000 mg/L, about 450,000 mg/L to about1,100,000 mg/L, about 500,000 mg/L to about 1,100,000 mg/L, about600,000 mg/L to about 1,100,000 mg/L, about 700,000 mg/L to about1,100,000 mg/L, about 800,000 mg/L to about 1,100,000 mg/L, about900,000 mg/L to about 1,100,000 mg/L or about 1,000,000 mg/L to about1,100,000 mg/L.

In some embodiments, the ultra-high-density concentrated brine streamcontains at least one dissolved salt (e.g., NaCl) in an amount of atleast about 1 wt %, at least about 5 wt %, at least about 10 wt %, atleast about 15 wt %, at least about 20 wt %, at least about 25 wt %, atleast about 26 wt %, at least about 27 wt %, at least about 28 wt %, atleast about 29 wt %, at least about 30 wt %, at least about 35 wt %, atleast about 40 wt %, at least about 50 wt %, at least about 60 wt %, orat least about 70 wt % (and/or, in certain embodiments, up to thesolubility limit of the salt in the liquid stream). In some embodiments,the ultra-high-density concentrated brine stream comprises at least onedissolved salt in an amount in the range of about 1 wt % to about 10 wt%, about 1 wt % to about 20 wt %, about 1 wt % to about 25 wt %, about 1wt % to about 26 wt %, about 1 wt % to about 27 wt %, about 1 wt % toabout 28 wt %, about 1 wt % to about 29 wt %, about 1 wt % to about 30wt %, about 1 wt % to about 35 wt %, about 1 wt % to about 40 wt %,about 1 wt % to about 50 wt %, about 1 wt % to about 60 wt %, about 1 wt% to about 70 wt %, about 10 wt % to about 20 wt %, about 10 wt % toabout 25 wt %, about 10 wt % to about 26 wt %, about 10 wt % to about 27wt %, about 10 wt % to about 28 wt %, about 10 wt % to about 29 wt %,about 10 wt % to about 30 wt %, about 10 wt % to about 35 wt %, about 10wt % to about 40 wt %, about 10 wt % to about 50 wt %, about 10 wt % toabout 60 wt %, about 10 wt % to about 70 wt %, about 20 wt % to about 25wt %, about 20 wt % to about 26 wt %, about 20 wt % to about 27 wt %,about 20 wt % to about 28 wt %, about 20 wt % to about 29 wt %, about 20wt % to about 30 wt %, about 20 wt % to about 35 wt %, about 20 wt % toabout 40 wt %, about 20 wt % to about 50 wt %, about 20 wt % to about 60wt %, about 20 wt % to about 70 wt %, about 25 wt % to about 26 wt %,about 25 wt % to about 27 wt %, about 25 wt % to about 28 wt %, about 25wt % to about 29 wt %, or about 25 wt % to about 30 wt %, about 25 wt %to about 35 wt %, about 25 wt % to about 40 wt %, about 25 wt % to about50 wt %, about 25 wt % to about 60 wt %, about 25 wt % to about 70 wt %,about 30 wt % to about 40 wt %, about 30 wt % to about 50 wt %, about 30wt % to about 60 wt %, about 30 wt % to about 70 wt %, about 40 wt % toabout 50 wt %, about 40 wt % to about 60 wt %, about 40 wt % to about 70wt %, about 50 wt % to about 60 wt %, about 50 wt % to about 70 wt %,about 60 wt % to about 70 wt %.

In some embodiments, the total dissolved salt concentration of theultra-high-density concentrated brine stream may be relatively high. Incertain cases, the total dissolved salt concentration of theultra-high-density concentrated brine stream is at least about 50,000mg/L, at least about 80,000 mg/L, at least about 85,000 mg/L, at leastabout 90,000 mg/L, at least about 100,000 mg/L, at least about 150,000mg/L, at least about 180,000 mg/L, at least about 200,000 mg/L, at leastabout 250,000 mg/L, at least about 270,000 mg/L, at least about 300,000mg/L, at least about 350,000 mg/L, at least about 380,000 mg/L, at leastabout 400,000 mg/L, at least about 450,000 mg/L, at least about 480,000mg/L, at least about 500,000 mg/L, at least about 600,000 mg/L, at leastabout 700,000 mg/L, at least about 800,000 mg/L, at least about 900,000mg/L, at least about 1,000,000 mg/L, or at least about 1,100,000 mg/L,or at least about 1,200,000 mg/L (and/or, in certain embodiments, up tothe solubility limit of the salt in the liquid stream). In someembodiments, the total dissolved salt concentration of theultra-high-density concentrated brine stream is in the range of about10,000 mg/L to about 500,000 mg/L, about 50,000 mg/L to about 500,000mg/L, about 80,000 mg/L to about 500,000 mg/L, about 85,000 mg/L toabout 500,000 mg/L, about 90,000 mg/L to about 500,000 mg/L, about100,000 mg/L to about 500,000 mg/L, about 150,000 mg/L to about 500,000mg/L, about 180,000 mg/L to about 500,000 mg/L, about 200,000 mg/L toabout 500,000 mg/L, about 250,000 mg/L to about 500,000 mg/L, about280,000 mg/L to about 500,000 mg/L, about 300,000 mg/L to about 500,000mg/L, about 350,000 mg/L to about 500,000 mg/L, about 380,000 mg/L toabout 500,000 mg/L, about 400,000 mg/L to about 500,000 mg/L, or about450,000 mg/L to about 500,000 mg/L, about 10,000 mg/L to about 1,200,000mg/L, about 20,000 mg/L to about 1,200,000 mg/L, about 50,000 mg/L toabout 1,200,000 mg/L, about 80,000 mg/L to about 1,200,000 mg/L, about85,000 mg/L to about 1,200,000 mg/L, about 90,000 mg/L to about1,200,000 mg/L, about 100,000 mg/L to about 1,200,000 mg/L, about150,000 mg/L to about 1,200,000 mg/L, about 180,000 mg/L to about1,200,000 mg/L, about 200,000 mg/L to about 1,200,000 mg/L, about250,000 mg/L to about 1,200,000 mg/L, about 280,000 mg/L to about1,200,000 mg/L, about 300,000 mg/L to about 1,200,000 mg/L, about350,000 mg/L to about 1,200,000 mg/L, about 380,000 mg/L to about1,200,000 mg/L, about 400,000 mg/L to about 1,200,000 mg/L, about450,000 mg/L to about 1,200,000 mg/L, about 500,000 mg/L to about1,200,000 mg/L, about 600,000 mg/L to about 1,200,000 mg/L, about700,000 mg/L to about 1,200,000 mg/L, about 800,000 mg/L to about1,200,000 mg/L, about 900,000 mg/L to about 1,200,000 mg/L or about1,000,000 mg/L to about 1,200,000 mg/L.

In some embodiments, the ultra-high-density concentrated brine streamcontains a total amount of dissolved salts of at least about 1 wt %, atleast about 5 wt %, at least about 10 wt %, at least about 15 wt %, atleast about 20 wt %, at least about 25 wt %, at least about 26 wt %, atleast about 27 wt %, at least about 28 wt %, at least about 29 wt %, atleast about 30 wt %, at least about 35 wt %, at least about 40 wt %, atleast about 50 wt %, at least about 60 wt %, or at least about 70 wt %,or at least about 80 wt %. In some embodiments, the ultra-high-densityconcentrated brine stream comprises a total amount of dissolved salts inthe range of about 1 wt % to about 10 wt %, about 1 wt % to about 20 wt%, about 1 wt % to about 25 wt %, about 1 wt % to about 26 wt %, about 1wt % to about 27 wt %, about 1 wt % to about 28 wt %, about 1 wt % toabout 29 wt %, about 1 wt % to about 30 wt %, about 1 wt % to about 35wt %, about 1 wt % to about 40 wt %, about 1 wt % to about 50 wt %,about 1 wt % to about 60 wt %, about 1 wt % to about 70 wt %, about 1 wt% to about 80 wt %, about 10 wt % to about 20 wt %, about 10 wt % toabout 25 wt %, about 10 wt % to about 26 wt %, about 10 wt % to about 27wt %, about 10 wt % to about 28 wt %, about 10 wt % to about 29 wt %,about 10 wt % to about 30 wt %, about 10 wt % to about 35 wt %, about 10wt % to about 40 wt %, about 10 wt % to about 50 wt %, about 10 wt % toabout 60 wt %, about 10 wt % to about 70 wt %, about 10 wt % to about 80wt %, about 20 wt % to about 25 wt %, about 20 wt % to about 26 wt %,about 20 wt % to about 27 wt %, about 20 wt % to about 28 wt %, about 20wt % to about 29 wt %, about 20 wt % to about 30 wt %, about 20 wt % toabout 35 wt %, about 20 wt % to about 40 wt %, about 20 wt % to about 50wt %, about 20 wt % to about 60 wt %, about 20 wt % to about 70 wt %,about 20 wt % to about 80 wt %, about 25 wt % to about 26 wt %, about 25wt % to about 27 wt %, about 25 wt % to about 28 wt %, about 25 wt % toabout 29 wt %, or about 25 wt % to about 30 wt %, about 25 wt % to about35 wt %, about 25 wt % to about 40 wt %, about 25 wt % to about 50 wt %,about 25 wt % to about 60 wt %, about 25 wt % to about 70 wt %, about 25wt % to about 80 wt %, about 30 wt % to about 40 wt %, about 30 wt % toabout 50 wt %, about 30 wt % to about 60 wt %, about 30 wt % to about 70wt %, about 30 wt % to about 80 wt %, about 40 wt % to about 50 wt %,about 40 wt % to about 60 wt %, about 40 wt % to about 70 wt %, about 40wt % to about 80 wt %, about 50 wt % to about 60 wt %, about 50 wt % toabout 70 wt %, about 50 wt % to about 80 wt %, about 60 wt % to about 70wt %, about 60 wt % to about 80 wt %, or about 70 wt % to about 80 wt %.

According to some embodiments, a system for producing a concentratedbrine stream comprises a desalination system (e.g., a desalinationsystem configured to be transiently operated) and, optionally, apretreatment system and/or precipitation apparatus fluidly connected tothe desalination system. In certain cases, for example, a liquid feedstream comprising water and at least one dissolved salt may flow throughan optional pretreatment system prior to entering a desalination system.The optional pretreatment system may optionally comprise a separationapparatus, an ion-removal apparatus, a suspended solids removalapparatus, a pH adjustment apparatus, a volatile organic material (VOM)removal apparatus, and/or a filtration apparatus. In some cases, it maybe advantageous for a liquid feed stream to flow through a pretreatmentsystem prior to flowing through a desalination system in order to removeone or more contaminants (e.g., scaling ions, suspended solids,water-immiscible materials, etc.) that may impede operation of thedesalination system.

FIG. 4 is a schematic diagram of exemplary system 400 for producing aconcentrated brine stream, according to certain embodiments. In FIG. 4,system 400 comprises optional pretreatment system 402, desalinationsystem 416, and optional precipitation apparatus 418. As shown in FIG.4, pretreatment system 402 comprises optional separation apparatus 404configured to remove at least a portion of a suspended and/or emulsifiedimmiscible phase from a liquid stream, optional ion-removal apparatus406 configured to remove at least a portion of at least onescale-forming ion from a liquid stream, optional suspended solidsremoval apparatus 408 configured to remove at least a portion ofsuspended solids from a liquid stream, optional pH adjustment apparatus410 configured to adjust (i.e. increase or decrease) ormaintain/stabilize (e.g. via buffering) the pH of a liquid stream,optional volatile organic material (VOM) removal apparatus 412configured to remove at least a portion of VOM from a liquid stream,and/or optional filtration apparatus 414 configured to produce asubstantially solid material. Each component of system 400 for producinga concentrated brine stream may be fluidly connected to one or moreother components of system 400, either directly or indirectly. It shouldbe noted that each of the components of system 400 shown in FIG. 4 isoptional, and a system for producing a concentrated brine stream maycomprise any combination of the components shown in FIG. 4.

In operation, liquid feed stream 420 comprising a suspended and/oremulsified immiscible phase, a scale-forming ion, suspended solids,and/or a volatile organic material is flowed to separation apparatus404. Separation apparatus 404 removes at least a portion of thesuspended and/or emulsified immiscible phase to produceimmiscible-phase-diminished stream 422, which contains less of theimmiscible phase than feed stream 420. In certain embodiments,separation apparatus 404 also produces immiscible-phase-enriched stream424, which contains more of the immiscible phase than feed stream 420.Immiscible-phase-diminished stream 422 is then made to flow toion-removal apparatus 406. Ion-removal apparatus 406 removes at least aportion of at least one scale-forming ion from stream 422 to produceion-diminished stream 426, which contains less of at least onescale-forming ion than immiscible-phase-diminished stream 422. Incertain embodiments, ion-removal apparatus 406 also producesion-enriched stream 428, which contains more of at least onescale-forming ion than immiscible-phase-diminished stream 422.Ion-diminished stream 426 is then made to flow to suspended solidsremoval apparatus 408. Suspended solids removal apparatus 408 removes atleast a portion of suspended solids from ion-diminished stream 426 toproduce suspended-solids-diminished stream 430, which contains lesssuspended solids than ion-diminished stream 426. Optionally, suspendedsolids removal apparatus 408 may also produce suspended-solids-enrichedstream 432, which contains more suspended solids than ion-diminishedstream 426, and which may be flowed to filtration apparatus 414 to formsolid stream 434 and filtered liquid stream 436.Suspended-solids-diminished stream 430 is then made to flow to pHadjustment apparatus 410. pH adjustment apparatus 410 may, in certaincases, increase or decrease the pH of stream 430 to produce pH-adjustedstream 438. In some cases, chemicals 440 (e.g., one or more acids) maybe added in pH adjustment apparatus 410 to adjust (e.g., increase ordecrease) or maintain/stabilize (e.g., via buffering) the pH of stream430. pH-adjusted stream 438 is then made to flow to VOM removalapparatus 412. VOM removal apparatus 412 may remove at least a portionof VOM from pH-adjusted stream 438 to produce VOM-diminished stream 442,which contains less VOM than pH-adjusted stream 438. VOM removalapparatus 412 may also produce VOM-enriched stream 444, which containsmore VOM than pH-adjusted stream 438. VOM-diminished stream 442 is thenmade to flow to desalination system 416, which may be configured toremove at least a portion of at least one dissolved salt fromVOM-diminished stream 442. In some cases, desalination system 416 isconfigured to produce a substantially pure water stream 446 and aconcentrated brine stream 448. In certain embodiments, at least aportion of substantially pure water stream 446 is discharged from system400 and/or is recycled and returned to desalination system 416. Incertain cases, at least a portion of concentrated brine stream 448 ismade to flow to precipitation apparatus 418. Precipitation apparatus 418may be configured such that at least a portion of the dissolved saltwithin concentrated brine stream 448 is precipitated withinprecipitation apparatus 418 to produce solid stream 450 andwater-containing stream 452, which contains less dissolved salt thanconcentrated brine stream 448.

As shown in FIG. 4, a pretreatment system may comprise an optionalseparation apparatus configured to receive a liquid feed stream andremove at least a portion of a suspended and/or emulsified immisciblephase (e.g., a water-immiscible material) to produce animmiscible-phase-diminished stream, which contains less of theimmiscible phase than the liquid feed stream. As used herein, asuspended and/or emulsified immiscible phase refers to a material thatis not soluble in water to a level of more than 10% by weight at thetemperature and under the conditions at which the separation apparatusoperates. In some embodiments, the suspended and/or emulsifiedimmiscible phase comprises oil and/or grease. As used herein, the term“oil” refers to a fluid that is generally more hydrophobic than waterand is not miscible or soluble in water, as is known in the art. Thus,the oil may be a hydrocarbon in some embodiments, but in otherembodiments, the oil may comprise other hydrophobic fluids.

In certain embodiments, the separation apparatus is configured to removea relatively large percentage of water-immiscible material from thestream fed to the separation apparatus. For example, in someembodiments, the amount (in weight percentage, wt %) of at least onewater-immiscible material within the immiscible-phase-diminished streamexiting the separation apparatus (e.g., stream 422 in FIG. 4) is atleast about 50%, at least about 75%, at least about 90%, at least about95%, or at least about 99% less than the amount of the at least onewater-immiscible material within the stream entering the separationapparatus (e.g., stream 420 in FIG. 4). To illustrate, if the streamexiting the separation apparatus contains 5 wt % water-immisciblematerial, and the stream entering the separation apparatus contains 50wt % water-immiscible material, then the stream exiting the separationapparatus contains 90% less water-immiscible than the stream enteringthe separation apparatus. In certain embodiments, the sum of the amountsof all water-immiscible materials within the stream exiting theseparation apparatus is at least about 50%, at least about 75%, at leastabout 90%, at least about 95%, or at least about 99% less than the sumof the amounts of all water-immiscible materials within the streamentering the separation apparatus.

In some embodiments, the separation apparatus comprises one or moreseparators. FIG. 5 shows a schematic diagram of an exemplary separationapparatus. As shown in FIG. 5, separation apparatus 404 comprisesoptional strainer 502, primary separator 504, optional secondaryseparator 506, and optional tank 508. In operation, liquid feed stream420 (e.g., corresponding to liquid feed stream 420 in FIG. 4) flowsthrough optional strainer 502. Strainer 502 may be configured to preventparticles having a certain size from passing through strainer 502 toprimary separator 504. Liquid stream 510, which is the portion of liquidfeed stream 420 that passes through strainer 502, may then flow toprimary separator 504. In primary separator 504, water may besubstantially separated from a suspended and/or emulsified immisciblephase to produce first immiscible-phase-diminished stream 512, whichcontains less of the suspended and/or emulsified immiscible phase thanstream 510, and first immiscible-phase-enriched stream 514, whichcontains more of the suspended and/or emulsified immiscible phase thanstream 510. Immiscible-phase-diminished stream 512 may flow to tank 508.

In some cases, immiscible-phase-enriched stream 514 may flow to optionalsecondary separator 506. In secondary separator 506, any water remainingin stream 514 may be separated from the suspended and/or emulsifiedimmiscible phase to produce second immiscible-phase-diminished stream516 and second immiscible-phase-enriched stream 424. Secondimmiscible-phase-enriched stream 424 may be discharged from separationapparatus 404, and second immiscible-phase-diminished stream 516 may beflowed to tank 508. Immiscible-phase-diminished stream 422 formed bycombining streams 512 and 516 may then be discharged from separationapparatus 404. In some embodiments, immiscible-phase-diminished stream422 is made to flow to another component of pretreatment system 402(e.g., ion-removal apparatus 406, suspended solids removal apparatus408, pH adjustment apparatus 410, VOM removal apparatus 412).Alternatively, in some embodiments, at least a portion ofimmiscible-phase-diminished stream 422 is discharged from pretreatmentsystem 402 and made to flow to desalination system 416.

The primary separator of a separation apparatus may be any type ofseparator known in the art. In some cases, the primary separator atleast partially separates a portion of a suspended and/or emulsifiedimmiscible phase from an aqueous stream via gravity, centrifugal force,adsorption, and/or a physical barrier. According to certain embodiments,the primary separator comprises an induced gas flotation (IGF)separator, a dissolved gas flotation (DGF) separator, a hydrocyclone(e.g., a de-oiling hydrocyclone), a corrugated plate interceptor, anadsorption media filter, a coalescing media filter, a membrane filter, agravity separator (e.g., an American Petroleum Institute (API)separator), and/or a skimmer.

According to certain embodiments, the primary separator is an inducedgas flotation (IGF) separator. An IGF separator generally refers to adevice configured to introduce bubbles of a gas into a volume of aliquid, where the gas bubbles adhere to particles (e.g., droplets ofwater-immiscible material, small solid particles) within the liquidvolume and cause the particles to float to the surface of the liquidvolume. In a particular embodiment, the gas is air, and the IGFseparator is referred to as an induced air flotation (IAF) separator.Other examples of suitable gases include, but are not limited to, carbondioxide (CO₂), nitrogen (N₂), and/or natural gas. In some cases, use ofan IGF separator may be associated with certain advantages, such asremoving at least a portion of one or more VOMs and/or one or moredissolved gases (e.g., hydrogen sulfide).

In some embodiments, the separation apparatus further comprises asecondary separator fluidly connected to the primary separator. In somecases, the secondary separator is configured to remove at least aportion of a suspended and/or emulsified immiscible phase from animmiscible-phase-enriched stream received from the primary separator.The secondary separator may be any type of separator known in the art.In some cases, the secondary separator at least partially separates aportion of a suspended and/or emulsified immiscible phase from anaqueous stream via gravity, centrifugal force, adsorption, and/or aphysical barrier. For example, the secondary separator may comprise adissolved gas flotation (DGF) separator, a gravity separator (e.g., anAPI separator), an induced gas flotation (IGF) separator, a hydrocyclone(e.g., a de-oiling hydrocyclone), a corrugated plate interceptor, anadsorption media filter, a coalescing media filter, a membrane filter,and/or a skimmer.

According to certain embodiments, the secondary separator comprises adissolved gas flotation (DGF) separator. A DGF separator generallyrefers to a device configured to dissolve a gas into a liquid volume. Insome cases, the gas may be dissolved in the liquid volume through thegeneration of very high pressure zones. In certain embodiments, thedissolved gas may precipitate as small gas bubbles (e.g., having anaverage diameter of about 10 microns or less). In some embodiments, thesmall gas bubbles nucleate on particles (e.g., droplets ofwater-immiscible material, suspended solid particles), and the bubblesand associated particles float to the surface of the liquid volume. Incertain embodiments, the gas is air, and the DGF separator is referredto as a dissolved air flotation (DAF) separator. In certain cases, thedensity of air bubbles in a liquid volume is relatively low. In somecases, the relatively low density of air bubbles advantageouslyincreases the rate of buoyancy-driven separation between water andwater-immiscible materials.

In some embodiments, the secondary separator comprises a gravityseparator. For example, in certain cases, the gravity separatorcomprises a settling tank. In certain embodiments, water andwater-immiscible material in a stream received by the gravity separator(e.g., an immiscible-phase-enriched stream) may be at least partiallyphysically separated within the settling tank. In some cases, forexample, water present in the stream received by the gravity separatormay settle at the bottom of a settling tank, while water-immisciblematerial may float to the top of the settling tank. In certainembodiments, this separation may be at least partially attributed todifferences in the specific gravity of water and the water-immisciblematerial. In certain cases, at least a portion of the water-immisciblematerial (e.g., oil, grease) may be recovered from the settling tank.The water-immiscible material may subsequently be stored and/ortransported off-site.

In some embodiments, water recovered from the stream received by thesecondary separator may be combined with the immiscible-phase-diminishedstream produced by the primary separator. In certain cases, theimmiscible-phase-diminished streams produced by the primary and/orsecondary separator may be made to flow to one or more buffer tanksand/or storage tanks. In certain cases, the immiscible-phase-diminishedstreams may be made to flow to other components of a pretreatment system(e.g., ion-removal apparatus, suspended solids removal apparatus, pHadjustment apparatus, VOM removal apparatus). In some cases, theimmiscible-material-diminished streams may be made to flow to adesalination system.

In some embodiments, the primary separator and/or secondary separatormay be configured to remove droplets of the immiscible phase havingrelatively small diameters. In certain embodiments, the primaryseparator and/or secondary separator are configured to remove dropletsof the immiscible phase having a diameter of about 200 microns or less,about 150 microns or less, about 100 microns or less, about 50 micronsor less, about 20 microns or less, about 10 microns or less, about 5microns or less, or about 1 micron or less. In certain cases, theprimary separator and/or secondary separator are configured to removedroplets of the immiscible phase having an average diameter of at leastabout 1 micron, at least about 5 microns, at least about 10 microns, atleast about 20 microns, at least about 50 microns, at least about 100microns, at least about 150 microns, or at least about 200 microns.Combinations of the above-noted ranges (e.g., about 1 micron to about200 microns, about 1 micron to about 100 microns, about 1 micron toabout 50 microns, about 1 micron to about 10 microns) are also possible.

In some embodiments, the separation apparatus comprises one or moreadditional components. According to some embodiments, the separationapparatus further comprises an optional strainer positioned upstream ofthe primary separator and/or the secondary separator. A strainergenerally refers to a device configured to prevent the passage ofparticles having a certain size through the strainer. In someembodiments, the strainer is configured to prevent the passage ofparticles having an average diameter of at least about 0.1 mm, at leastabout 0.5 mm, at least about 1 mm, at least about 2 mm, at least about 5mm, at least about 10 mm, at least about 15 mm, or at least about 20 mm.Non-limiting examples of suitable strainers include basket strainers,duplex basket strainers (e.g., twin basket strainers), Y-strainers,T-strainers, inline strainers, automatic self-cleaning strainers, platestrainers (e.g., expanded cross-section strainers), scraper strainers,and/or magnetic strainers.

In some embodiments, the separation apparatus further comprises one ormore optional buffer tanks. In some embodiments, one or more buffertanks are positioned between the primary separator and/or secondaryseparator and other components of a pretreatment system.

In certain cases, the separation apparatus further comprises one or moreadditional separators. In some embodiments, the one or more separatorsare positioned upstream of the primary separator. The one or moreupstream separators may be any type of separator known in the art. Insome embodiments, the one or more upstream separators at least partiallyseparate the suspended and/or emulsified immiscible phase from water viagas flotation, gravity, centrifugal force, adsorption, and/or a physicalbarrier. In some embodiments, the one or more upstream separatorscomprise a gravity separator (e.g., an American Petroleum Institute(API) separator), an IGF separator, a DGF separator, a hydrocyclone(e.g., a de-oiling hydrocyclone), a corrugated plate interceptor, anadsorption media filter, a coalescing media filter, and/or a membranefilter.

In certain embodiments, the one or more upstream separators comprise agravity separator. In some cases, the gravity separator is an AmericanPetroleum Institute (API) separator. An API separator generally refersto a separator configured to separate water and water-immisciblematerial based on the specific gravity difference between water and thewater-immiscible material (e.g., through settling). In some cases, anAPI separator may be used to separate relatively large amounts of waterand water-immiscible material. In certain embodiments, an API separatorcomprises coalescing media. In some cases, an API separator comprisesparallel plates. In certain embodiments, the presence of parallel platesin the API separator may advantageously reduce the residence timerequired for separation by settling in the API separator.

It should be noted that the primary separator, optional secondaryseparator, and/or one or more optional upstream separators may be thesame type of separator or different types of separators.

According to certain embodiments, the pretreatment system can comprisean optional ion-removal apparatus. The ion-removal apparatus can beconfigured to remove at least a portion of at least one scale-formingion from an input stream received by the ion-removal apparatus toproduce an ion-diminished stream. Generally, the ion-diminished streamcontains less of the scale-forming ion (e.g., a scale-forming cationand/or a scale-forming anion) relative to the input stream received bythe ion-removal apparatus. The use of the ion-removal apparatus toremove scale-forming ions can reduce the level of scaling within unitoperations downstream of the ion-removal apparatus (e.g., a desalinationsystem). In certain embodiments, the ion-removal apparatus removes atleast a portion of at least one scale-forming ion while allowing adissolved salt (e.g., a dissolved monovalent salt) to remain dissolvedin the aqueous stream transported out of the ion-removal apparatus.

The ion-removal apparatus can be configured to remove any scale-formingion that is desired to be removed. Those of ordinary skill in the artare familiar with scale-forming ions, which are ions that tend to formsolid scale when present in concentrations exceeding their solubilitylevels. In some cases, at least one scale-forming ion is a scale-formingcation (e.g., a multivalent cation). Non-limiting examples ofscale-forming cations include Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺. In some cases,at least one scale-forming ion is a scale-forming anion (e.g., amultivalent anion). Non-limiting examples of scale-forming anionsinclude carbonate anions (CO₃ ²⁻), bicarbonate anions (HCO₃ ⁻), sulfateanions (SO₄ ²⁻), bisulfate anions (HSO₄ ⁻), and dissolved silica (e.g.,SiO₂(OH)₂ ²⁻, SiO(OH)³⁻, (SiO₃ ²⁻)_(n). In certain embodiments, theion-removal apparatus is configured to remove at least a portion of atleast one scale-forming ion in an aqueous feed stream while allowing adissolved monovalent salt (e.g., NaCl) to remain dissolved in theaqueous stream transported out of the ion-removal apparatus.

In some instances, the scale-forming ions that are removed from theliquid feed stream using the ion-removal apparatus may be sparinglysoluble (e.g., having a solubility of less than about 1 gram per 100grams of water, less than about 0.1 grams per 100 grams of water, orless than about 0.01 grams per 100 grams of water (or lower) at 20° C.).Therefore, according to some embodiments, such scale-forming ions may beprone to scaling within various parts of a pretreatment system and/or adesalination system. Examples of sparingly soluble salts containingscale-forming ions include, but are not limited to, calcium carbonate(CaCO₃), which has a solubility of about 0.000775 grams per 100 grams ofwater at 20° C.; calcium sulfate (CaSO₄), which has a solubility ofabout 0.264 grams per 100 grams of water at 20° C.; magnesium hydroxide(Mg(OH)₂), which has a solubility of about 0.0009628 grams per 100 gramsof water at 20° C.; and barium sulfate (BaSO₄), which has a solubilityof about 0.000285 grams per 100 grams of water at 20° C. The ion-removalapparatus can be configured, according to certain embodiments, such thatremoval of the scale-forming ions inhibits or prevents scaling of solidsalts comprising the scale-forming ions during operation of thepretreatment system and/or the desalination system.

In certain embodiments, the ion-removal apparatus is configured toremove a relatively large percentage of the dissolved scale-forming ionsfrom the feed stream. According to certain embodiments, the ion-removalapparatus can be configured to produce an ion-diminished stream in whichthe concentration, in milligrams per liter, of at least onescale-forming ion (e.g., Ca²⁺) within the ion-diminished stream (e.g.,stream 426 in FIG. 4) is about 750 mg/L or less, about 500 mg/L or less,about 200 mg/L or less, about 100 mg/L or less, about 50 mg/L or less,about 20 mg/L or less, about 10 mg/L or less, about 5 mg/L or less,about 2 mg/L or less, about 1 mg/L or less, about 0.1 mg/L or less, orabout 0 mg/L. In some embodiments, the concentration of at least onescale-forming ion within the ion-diminished stream is in the range ofabout 0 mg/L to about 750 mg/L, about 0 mg/L to about 500 mg/L, about 0mg/L to about 200 mg/L, about 0 mg/L to about 100 mg/L, about 0 mg/L toabout 50 mg/L, about 0 mg/L to about 20 mg/L, about 0 mg/L to about 10mg/L, about 0 mg/L to about 5 mg/L, about 0 mg/L to about 2 mg/L, orabout 0 mg/L to about 1 mg/L. In some embodiments, the ion-diminishedstream is substantially free of at least one scale-forming ion.

In some embodiments, the ion-removal apparatus is configured to producean ion-diminished stream in which the total concentration, in milligramsper liter, of scale-forming ions within the ion-diminished stream isabout 2600 mg/L or less, about 2500 mg/L or less, about 2000 mg/L orless, about 1800 mg/L or less, about 1500 mg/L or less, about 1000 mg/Lor less, about 900 mg/L or less, about 800 mg/L or less, about 700 mg/Lor less, about 600 mg/L or less, about 500 mg/L or less, about 200 mg/Lor less, about 100 mg/L or less, 50 mg/L or less, about 20 mg/L or less,about 10 mg/L or less, about 5 mg/L or less, about 2 mg/L or less, about1 mg/L or less, about 0.1 mg/L or less, or about 0 mg/L. In someembodiments, the total concentration of scale-forming ions within theion-diminished stream is in the range of about 0 mg/L to about 2600mg/L, about 0 mg/L to about 2500 mg/L, about 0 mg/L to about 2000 mg/L,about 0 mg/L to about 1800 mg/L, about 0 mg/L to about 1500 mg/L, about0 mg/L to about 1000 mg/L, about 0 mg/L to about 500 mg/L, about 0 mg/Lto about 200 mg/L, about 0 mg/L to about 100 mg/L, about 0 mg/L to about50 mg/L, about 0 mg/L to about 20 mg/L, about 0 mg/L to about 20 mg/L,about 0 mg/L to about 10 mg/L, about 0 mg/L to about 5 mg/L, about 0mg/L to about 2 mg/L, or about 0 mg/L to about 1 mg/L. In someembodiments, the ion-diminished stream exiting the ion-removal apparatusis substantially free of scale-forming ions.

In certain embodiments, the ion-removal apparatus is configured toproduce an ion-diminished stream in which the concentration, in molesper liter (i.e., molarity), of at least one scale-forming ion within thestream exiting the ion-removal apparatus (e.g., stream 426 in FIG. 4) isat least about 50%, at least about 75%, at least about 90%, at leastabout 95%, or at least about 99% less than the concentration of the atleast one scale-forming ion within the stream entering the ion-removalapparatus (e.g., stream 422 in FIG. 4). In certain embodiments, the sumof the concentrations, in moles per liter, of all scale-forming ionswithin the stream exiting the ion-removal apparatus is at least about50%, at least about 75%, at least about 90%, at least about 95%, or atleast about 99% less than the sum of the concentrations of allscale-forming ions within the stream entering the ion-removal apparatus.

A variety of types of ion-removal apparatuses may be used in theembodiments described herein. In some embodiments, the ion-removalapparatus comprises an ion-removal medium, which can be contained, forexample, within a vessel. In some embodiments, the ion-removal apparatuscomprises a chemical ion-removal apparatus. According to certainembodiments, the chemical ion-removal apparatus comprises one or moreion-removal compositions configured to induce precipitation of at leastone scale-forming ion. For example, the chemical ion-removal apparatuscan be configured to remove at least one ion using caustic soda (e.g.,NaOH), soda ash (e.g., Na₂CO₃), and/or a flocculent (e.g., an anionicpolymer). In some embodiments, the one or more ion-removal compositionscan be configured to induce precipitation of at least one scale-formingcation. For example, when caustic soda and/or soda ash are added to astream containing Ca²⁺ and/or Mg²⁺, at least a portion of Ca²⁺ and/orMg²⁺ contained within the stream may be precipitated as an insolublesolid such as, for example, calcium carbonate (CaCO₃) and/or magnesiumhydroxide (Mg(OH)₂). Without wishing to be bound by a particular theory,the addition of caustic soda may induce precipitation of certainscale-forming cations in a stream by increasing the pH of the stream. Insome cases, carbonate salts and/or hydroxide salts of the scale-formingcations have relatively low solubility at relatively high pH levels, andincreasing the pH of a stream containing scale-forming cations mayinduce precipitation of such carbonate salts and/or hydroxide salts ofthe scale-forming cations. In certain embodiments, the addition of sodaash may facilitate precipitation of carbonate salts of certainscale-forming anions by providing a supply of carbonate ions. In someembodiments, the one or more ion removal compositions can be configuredto induce precipitation of at least one scale-forming anion.

In some embodiments, the one or more ion removal compositions comprise aflocculent. A flocculent generally refers to a composition that causesrelatively large particles to form through aggregation of smallerparticles. In some embodiments, the relatively large particles mayprecipitate from a solution. Non-limiting examples of suitableflocculents include ferric chloride, polyaluminum chloride, activatedsilica, colloidal clays (e.g., bentonite), metallic hydroxides with apolymeric structure (e.g., alum, ferric hydroxide), starches and/orstarch derivatives (e.g., corn starch, potato starch, anionic oxidizedstarches, amine-treated cationic starches), polysaccharides (e.g., guargum), alginates, polyacrylamides (e.g., nonionic, anionic, or cationicpolyacrylamides), polyethylene-imines, polyamide-amines, polyamines,polyethylene oxide, and/or sulfonated compounds. Without wishing to bebound by a particular theory, certain flocculents may form largeparticles (e.g., large precipitates) by enmeshing smaller particles onformation and/or entrapping smaller particles through adhesion.

According to some embodiments, the flocculent comprises a polymer. Incertain cases, the flocculent may be a large-chain polymer. Withoutwishing to be bound by a particular theory, a large-chain polymerflocculent may facilitate the formation of large particles by adheringto a plurality of smaller particles. In some cases, a large-chainpolymer flocculent facilitates the formation of large particles ofincreased size and/or increased mechanical strength. In certainembodiments, the flocculent is an anionic polymer flocculent. Theanionic polymer flocculent may, in some cases, be used to removescale-forming cations. In certain embodiments, the flocculent is acationic polymer flocculent. The cationic polymer flocculent may, insome cases, be used to remove scale-forming anions.

It should be noted that mixtures of the above-mentioned ion removalcompositions and/or other ion removal compositions may also be used. Inaddition, if two or more ion removal compositions are added to a liquidfeed stream, the ion removal compositions may be added in any order.According to certain embodiments, caustic soda and a polymer flocculent(e.g., an anionic polymer flocculent) may be added to an aqueous feedstream. In certain cases, caustic soda, soda ash, and a polymerflocculent (e.g., an anionic polymer flocculent) may be added to aliquid feed stream.

In some embodiments, a chemical ion-removal apparatus comprises one ormore optional reaction tanks (e.g., one reaction tank, two reactiontanks, three reaction tanks, four reaction tanks, five reaction tanks,etc.). In each reaction tank, one or more ion-removal compositions maybe added to a liquid feed stream. In some embodiments, the residencetime of an aqueous stream flowing through the reaction tanks may berelatively short. According to some embodiments, the residence time ofan aqueous stream in at least one reaction tank is about 30 minutes orless, about 20 minutes or less, about 10 minutes or less, about 5minutes or less, about 2 minutes or less, or about 1 minute or less. Incertain embodiments, the residence time of an aqueous stream in eachreaction tank is about 30 minutes or less, about 20 minutes or less,about 10 minutes or less, about 5 minutes or less, about 2 minutes orless, or about 1 minute or less. In some embodiments, one or more of thereaction tanks comprise an agitator.

In an exemplary embodiment, a chemical ion-removal apparatus comprisesthree reaction tanks. In the first reaction tank, a first ion-removalcomposition (e.g., caustic soda) may be added to a liquid feed stream toproduce a first ion-diminished stream. In some cases, the firstion-diminished stream may be made to flow to the second reaction tank,and a second ion-removal composition (e.g., soda ash) and/or anadditional amount of the first ion-removal composition may be added tothe first ion-diminished stream to produce a second ion-diminishedstream. The second ion-diminished stream may then be flowed to the thirdreaction tank, and a third ion-removal composition (e.g., an anionicpolymer flocculent) may be added to the second ion-diminished stream toproduce a third ion-diminished stream. The third ion-diminished streammay be made to flow to another unit of the pretreatment system (e.g.,suspended solids removal apparatus, pH adjustment apparatus, VOM removalapparatus) for further treatment. In certain cases, the thirdion-diminished stream may be discharged from the pretreatment systemand, optionally, made to flow to a desalination system.

In certain embodiments, a chemical ion-removal apparatus furthercomprises an optional flocculation tank positioned downstream of one ormore reaction tanks. According to some embodiments, the flocculationtank may comprise an agitator (e.g., a slowly-rotating, low shearagitator). In some embodiments, conditions in the flocculation tank maybe selected to increase the size of precipitates formed by chemicalreactions in one or more upstream reaction tanks. For example, in somecases, a low shear agitator may be configured to promote motion ofprecipitates within the flocculation tank. In some cases, motion of theprecipitates may cause at least some of the precipitates to collide witheach other and adhere to each other, resulting in the formation oflarger precipitates. In some embodiments, it may be advantageous to havelarger precipitates, as they may have a reduced settling time. In someembodiments, the flocculation tank has a relatively large volume. Insome embodiments, the residence time of an aqueous stream in theflocculation tank is about 60 minutes or less, about 50 minutes or less,about 40 minutes or less, about 35 minutes or less, about 30 minutes orless, about 25 minutes or less, about 20 minutes or less, about 15minutes or less, or about 10 minutes or less. In some embodiments, theresidence time of an aqueous stream in the flocculation tank is in therange of about 10 minutes to about 20 minutes, about 10 minutes to about25 minutes, about 10 minutes to about 30 minutes, about 10 minutes toabout 35 minutes, about 10 minutes to about 40 minutes, about 10 minutesto about 50 minutes, about 10 minutes to about 60 minutes, about 20minutes to about 30 minutes, about 20 minutes to about 40 minutes, about20 minutes to about 50 minutes, or about 20 minutes to about 60 minutes,about 30 minutes to about 40 minutes, about 30 minutes to about 50minutes, or about 30 minutes to about 60 minutes.

In certain embodiments, the ion-removal apparatus comprises anelectrocoagulation apparatus. The electrocoagulation apparatus can beconfigured, in some embodiments, to remove at least a portion ofsuspended solids from the aqueous stream rather than, or in addition to,removing at least a portion of at least one scale-forming ion from theaqueous stream. Those of ordinary skill in the art are familiar withelectrocoagulation, in which short wave electrolysis can be used toremove at least a portion of multivalent ions and/or suspendedcontaminants.

In certain embodiments, the ion-removal apparatus comprises a resin bed.The resin bed contains, according to certain embodiments, anion-exchange resin. The resin bed can comprise, for example, an anionicselective resin bed and/or a cationic selective resin bed. In certainembodiments, the ion-removal apparatus is an ion-exchange apparatus. Theion-exchange apparatus may contain, for example, an ion-exchange medium.Those of ordinary skill in the art are familiar with the function ofion-exchange media, which generally remove at least one scale-formingion from a solution and, in some but not all cases, replace thescale-forming ion(s) with one or more monovalent ion(s). For example, incertain embodiments, the ion-exchange medium functions by contacting theaqueous solution containing the scale-forming ion(s), after which atleast a portion of the scale-forming ions are captured by theion-exchange medium and at least a portion of the monovalent ionsoriginally contained within the ion-exchange medium are released intothe aqueous solution. In some such embodiments, the ion-exchange mediumcomprises an ion exchange resin.

Those of ordinary skill in the art would be capable of selecting anappropriate ion-removal medium (e.g., an ion-exchange medium or otherion-removal medium) for use in the ion-removal apparatus based upon thetypes of scale-forming ions dissolved in the stream fed to theion-removal apparatus, the concentration of said ions, and the flow rateat which one desires to operate the ion-removal apparatus, among otherfactors. In some embodiments, a column (e.g., a packed column) can beused to perform the ion-removal operation. For example, in someembodiments, the liquid feed stream can be fed to one or more packedcolumns containing an ion-exchange resin or other ion-removal medium,which may be used to remove at least a portion of the scale-formingion(s) from the liquid stream. One of ordinary skill in the art, giventhe present disclosure, would be capable of designing a variety of othersuitable configurations for performing the ion-removal steps describedherein.

In some embodiments, the pretreatment systems described herein comprisean optional suspended solids removal apparatus. The suspended solidsremoval apparatus can be configured, according to certain embodiments,to remove at least a portion of suspended solids from an input streamreceived by the suspended solids removal apparatus to produce asuspended-solids-diminished stream. Generally, the suspended solidsdiminished stream contains a smaller quantity of suspended solids thanthe input stream received by the suspended solids removal apparatus.

The suspended solids removal apparatus can be configured to remove anysuspended solids that may be present in the stream fed to the suspendedsolids removal apparatus. According to certain embodiments, thesuspended solids removal apparatus can be configured to remove particlesthat remain in suspension in water as a colloid or due to the motion ofthe water. In some embodiments, the suspended solids removal apparatuscan be configured to remove dirt, precipitated salts, organic solids(e.g., pathogens such as bacteria, Giardia, and the like), and/or anyother solid material. In some embodiments, the suspended solids that areremoved by the suspended solids removal apparatus comprise particulatesolids.

In certain embodiments, the suspended solids removal apparatus isconfigured to remove a relatively large percentage of the suspendedsolids from the stream fed to the suspended solids removal apparatus.For example, in some embodiments, the amount (in weight percentage, wt%) of at least one suspended solid material within the stream exitingthe suspended solids removal apparatus (e.g., stream 430 in FIG. 4) isat least about 50%, at least about 75%, at least about 90%, at leastabout 95%, or at least about 99% less than the amount of the at leastone suspended solid material within the stream entering the suspendedsolids removal apparatus (e.g., stream 426 in FIG. 4). In certainembodiments, the sum of the amounts of all suspended solid materialswithin the stream exiting the suspended solids removal apparatus is atleast about 50%, at least about 75%, at least about 90%, at least about95%, or at least about 99% less than the sum of the amounts of allsuspended solid materials within the stream entering the suspendedsolids removal apparatus.

A variety of types of devices may be used in the suspended solidsremoval apparatuses described herein. In some embodiments, the suspendedsolids removal apparatus comprises a filter, a gravity settler, and/or acoagulant-induced flocculator. A filter generally refers a deviceconfigured to inhibit passage of certain materials (e.g., particles of acertain size) from one side of the device to the other side of thedevice. A gravity settler generally refers to a device that promotesseparation of suspended solids from a liquid through gravity (e.g., asettling tank). A coagulant-induced flocculator generally refers to adevice in which a coagulant is added to a volume of liquid to induceflocculation. Non-limiting examples of coagulants include ferricchloride, alum, ferrous sulfate, ferric sulfate, ferric chloride,cationic polymer, calcium hydroxide (e.g., lime), calcium oxide (e.g.,quicklime), sodium aluminate, ferric aluminum chloride, ferric chloridesulfate, magnesium carbonate, aluminum chlorohydrate, polyaluminumchloride, polyaluminum sulfate chloride, polyaluminum silicate chloride,forms of polyaluminum chloride with organic polymers, polyferric sulfateand ferric salts with polymers, and/or polymerized aluminum-iron blends.

According to some embodiments, the gravity settler comprises aclarifier. A clarifier generally refers to a tank (e.g., a settlingtank) that is configured for substantially continuous removal of solids.In some embodiments, the clarifier is an inclined-plate clarifier (e.g.,a lamella clarifier). An inclined-plate clarifier generally refers to adevice comprising a plurality of inclined plates. In operation, a liquidstream may enter the inclined-plate clarifier, and solid particles maybegin to settle on one or more of the inclined plates. In some cases,when a solid particle settles on an inclined plate, it adheres to otherparticles that have settled on the plate, and the particles slide downthe inclined plate to the bottom of the clarifier, where they arecollected as a solid-containing stream. In some embodiments, thesolid-containing stream may be transported to a filtration apparatus, asdescribed in further detail herein. In certain embodiments, theremaining water may exit the clarifier as a suspended-solids-diminishedstream.

According to some embodiments, the suspended solids removal apparatuscomprises a filter. In some embodiments, the filter is a polishingfilter. A polishing filter generally refers to a filter configured toprevent passage of relatively small particles and/or remove lowconcentrations of dissolved material. Examples of a suitable polishingfilter include, but are not limited to, a granular bed filter (e.g., amedia filter) and a bag filter. A granular bed filter refers to a filterthat comprises one or more types of granular filtration media (e.g.,sand, crushed anthracite coal, garnet sand, granular activated carbon,diatomaceous earth medium). In some embodiments, the polishing filter isconfigured to remove particles having an average diameter of at leastabout 0.1 micron, at least about 0.5 microns, at least about 1 micron,at least about 2 microns, at least about 5 microns, at least about 10microns, at least about 15 microns, at least about 20 microns, or atleast about 25 microns.

In certain embodiments, the pretreatment system comprises an optional pHadjustment apparatus configured to receive an input stream comprisingscale-forming ions and to adjust (e.g., increase or decrease) ormaintain/stabilize (e.g., via buffering) the pH of the input stream toproduce a pH-adjusted stream. In certain embodiments, adjusting ormaintaining/stabilizing the pH of the input stream can be performedwithout dissolving any particles that precipitated (e.g., due toaddition of an ion-removal composition in the ion-removal apparatus). Insome embodiments, the pH-adjusted stream has a pH in the range of about6 to about 8, about 6.5 to about 7.5, about 6.8 to about 7.2, or about6.9 to about 7.1. In some embodiments, the pH-adjusted stream has a pHof about 7.0.

In some embodiments, the pH adjustment apparatus is configured to reducethe pH of the aqueous input stream. In certain cases, reducing the pH ofthe aqueous input stream can be performed in order to inhibitscale-forming ions from precipitating. In some embodiments, the pH of anaqueous feed stream may be reduced by adding a pH-adjusting compositionto the feed stream. For example, in certain embodiments, an acid may beadded to the feed stream to reduce the pH of the stream. Non-limitingexamples of suitable acids include hydrochloric acid, sulfuric acid,phosphoric acid, nitric acid, and/or maleic acid. In some embodiments, abase may be added to the feed stream to increase the pH of the stream.Non-limiting examples of suitable bases include caustic soda, potassiumhydroxide, carbon dioxide, calcium hydroxide (e.g., lime), and/orcalcium oxide (e.g., quicklime).

As shown in FIG. 4, the pH of input stream 430 can be reduced by addingchemicals via stream 440, according to some embodiments. For example, anacidic composition can be added to pH adjustment apparatus 410 to reducethe pH of stream 430, in certain embodiments. The pH adjustmentapparatus may be fluidly connected to one or more other unit operationsof system 400, either directly or indirectly.

In some embodiments, the pH adjustment apparatus comprises one or morereaction tanks. The reaction tanks may be configured to facilitate thereaction of an aqueous stream and one or more reagents (e.g., a pHadjustment composition). In some cases, for example, one or morereaction tanks comprise a pH adjustment composition inlet and/or anagitator. In some cases, one or more reaction tanks comprise one or morepH sensors. In certain embodiments, one or more reaction tanks comprisetwo or more pH sensors. In certain cases, the pH adjustment apparatusfurther comprises a pH adjustment composition tank fluidly connected(e.g., directly fluidly connected) to one or more reaction tanks. The pHadjustment composition tank may, for example, be configured to containan amount of the pH adjustment composition. In some cases, the pHadjustment composition may comprise an acid (e.g., a strong acid) or abase (e.g., a strong base) having a relatively high concentration. Insome cases, the pH adjustment composition tank may be a single-walledtank. In some cases, the pH adjustment composition tank may be adouble-walled tank. It may be advantageous, in some cases, for the pHadjustment composition tank to be double-walled to reduce the risk ofinjury in the case of a leak. For example, a leak in a first wall of adouble-walled tank may be contained by the second wall of thedouble-walled tank. In some cases, the pH adjustment system furthercomprises a vapor containment system fluidically connected to the pHadjustment composition tank. In some cases, the vapor containment systemmay comprise a water-containing tank. In certain cases, thewater-containing tank may comprise an amount of water, and vapor fromthe pH adjustment composition tank may be bubbled through the water ofthe water-containing tank. The pH adjustment apparatus may furthercomprise one or more conduits connecting various components of the pHadjustment apparatus. In some cases, one or more conduits (e.g.,conduits connecting the pH adjustment composition tank and one or morereaction tanks) may be double-walled.

In certain embodiments, the pretreatment system comprises an optionalvolatile organic material (VOM) removal apparatus. The VOM removalapparatus can be configured to remove at least a portion of VOM from aninput stream received by the VOM removal apparatus to produce aVOM-diminished stream. Generally, the VOM-diminished stream contains VOMin an amount that is less that the amount of VOM in the input streamreceived by the VOM removal apparatus.

The term “volatile organic material” or “VOM” is used herein to describeorganic materials that at least partially evaporate at 25° C. and 1atmosphere. In certain embodiments, the volatile organic material has aboiling point of less than or equal to 450° C. at 1 atmosphere. VOMincludes volatile organic compounds (VOCs) and semi-volatile organiccompounds (SVOCs). Examples of VOCs that can be at least partiallyremoved by the VOM removal apparatus include, but are not limited to,acetone; 1,1,1,2-tetrachloroethane; 1,1,1-trichloroethane;1,1,2,2-tetrachloroethane; 1,1,2-trichloroethane; 1,1-dichloroethane;1,1-dichloroethene; 1,1-dichloropropene; 1,2,3-trichlorobenzene;1,2,3-trichloropropane; 1,2,4-trichlorobenzene; 1,2,4-trimethylbenzene;1,2-dibromo-3-chloropropane; 1,2-dibromoethane; 1,2-dichlorobenzene;1,2-dichloroethane; 1,2-dichloropropane; 1,3,5-trimethylbenzene;1,3-dichlorobenzene; 1,3-dichloropropane; 1,4-dichlorobenzene;2,2-dichloropropane; 2-butanone; 2-chloroethyl vinyl ether;2-chlorotoluene; 2-hexanone; 4-chlorotoluene; 4-methyl-2-pentanone;benzene; bromobenzene; bromochloromethane; bromodichloromethane;bromoform; carbon disulfide; carbon tetrachloride; chlorobenzene;chloroethane; chloroform; cis-1,2-dichloroethene;cis-1,3-dichloropropene; dibromochloromethane; dibromomethane;dichlorodifluoromethane; ethylbenzene; hexachlorobutadiene;isopropylbenzene; m-xylenes; p-xylenes; bromomethane; chloromethane;methylene chloride; n-butylbenzene; n-propylbenzene; naphthalene;o-xylene; p-isopropyltoluene; sec-butylbenzene; styrene;tert-butylbenzene; tetrachloroethene; toluene; trans-1,2-dichloroethene;trans-1,3-dichloropropene; trichloroethene; trichlorofluoromethane;vinyl acetate; and vinyl chloride. Examples of SVOCs that can be atleast partially removed by the VOM removal apparatus include, but arenot limited to, 2,4,5-trichlorophenol; 2,4,6-trichlorophenol;2,4-dichlorophenol; 2,4-dimethylphenol; 2,4-dinitrophenol;2,4-dinitrotoluene; 2,6-dinitrotoluene; 2-chloronaphthalene;2-chlorophenol; 2-methylnaphthalene; 2-methylphenol; 2-nitroaniline;2-nitrophenol; 3,3′-dichlorobenzidine; 3-nitroaniline;4,6-dinitro-2-methylphenol; 4-bromophenyl phenyl ether;4-chloro-3-methylphenol; 4-chloroaniline; 4-chlorophenyl phenyl ether; 3& 4-methylphenol; 4-nitroaniline; 4-nitrophenol; acenaphthene;acenaphthylene; anthracene; benzo(a)anthracene; benzo(a)pyrene;benzo(b)fluoranthene; benzo(g,h,i)perylene; benzo(k)fluoranthene;benzoic acid; benzyl alcohol; bis(2-chloroethoxy)methane;bis(2-chloroethyl)ether; bis(2-chloroisopropyl)ether;bis(2-ethylhexyl)phthalate; butyl benzyl phthalate; chrysene; di-n-butylphthalate; di-n-octyl phthalate; dibenz(a,h)anthracene; dibenzofuran;diethyl phthalate; dimethyl phthalate; fluoranthene; fluorene;hexachlorobenzene; hexachlorocyclopentadiene; hexachloroethane;indeno(1,2,3-cd)pyrene; isophorone; n-nitroso-di-n-propylamine;n-nitrosodiphenylamine; nitrobenzene; pentachlorophenol; phenanthrene;phenol; and pyrene.

In certain embodiments, the VOM removal apparatus is configured toremove a relatively large percentage of the VOM from the stream fed tothe VOM removal apparatus. For example, in some embodiments, the amount(in weight percentage, wt %) of at least one VOM within the streamexiting the VOM removal apparatus (e.g., stream 442 in FIG. 4) is atleast about 50%, at least about 75%, at least about 90%, at least about95%, or at least about 99% less than the amount of the at least one VOMwithin the stream entering the VOM removal apparatus (e.g., stream 438in FIG. 4). In certain embodiments, the sum of the amounts of all VOMwithin the stream exiting the VOM removal apparatus is at least about50%, at least about 75%, at least about 90%, at least about 95%, or atleast about 99% less than the sum of the amounts of all VOM within thestream entering the VOM removal apparatus. The VOM removal apparatus maybe fluidly connected to one or more other unit operations of thepretreatment system, desalination system, and/or precipitationapparatus, either directly or indirectly.

A variety of types of VOM removal apparatuses may be used in theembodiments described herein. In some embodiments, the VOM removalapparatus comprises a carbon bed filter and/or an air stripper. In someembodiments, the air stripper comprises a packed bed stripper, alow-profile air stripper, and/or an aeration stripper. In certainembodiments, the carbon bed comprises activated carbon.

According to some embodiments, the pretreatment system comprises anoptional filtration apparatus. In some embodiments, the filtrationapparatus may be configured to remove at least a portion of water from asolid-containing stream to form a substantially solid material and afiltered liquid stream. The substantially solid material may, in somecases, comprise at least a portion of a precipitated salt (e.g., amonovalent salt, a divalent salt). In certain embodiments, thesubstantially solid material may be a filter cake. In some embodiments,the filter cake may comprise a plurality of solid particles, wherein atleast a portion of the solid particles are in direct contact withanother solid particle. In certain cases, at least about 60%, at leastabout 70%, at least about 80%, at least about 90%, at least about 95%,or at least about 99% of the solid particles in the filter cake are indirect contact with another solid particle. In some cases, the filtercake has a relatively low liquid content. In some embodiments, thefilter cake has a liquid content of about 90 wt % or less, about 85 wt %or less, about 80 wt % or less, about 75 wt % or less, about 70 wt % orless, about 65 wt % or less, about 60 wt % or less, about 55 wt % orless, about 50 wt % or less, about 40 wt % or less, about 30 wt % orless, about 25 wt % or less, about 20 wt % or less, about 15 wt % orless, or about 10 wt % or less. In certain embodiments, the filter cakehas a liquid content in the range of about 10 wt % to about 90 wt %,about 10 wt % to about 85 wt %, about 10 wt % to about 80 wt %, about 10wt % to about 75 wt %, about 10 wt % to about 70 wt %, about 10 wt % toabout 60 wt %, about 10 wt % to about 55 wt %, about 10 wt % to about 50wt %, about 10 wt % to about 40 wt %, about 10 wt % to about 30 wt %, orabout 10 wt % to about 20 wt %.

In some cases, the filtration apparatus comprises a filter (e.g., avacuum drum filter or a filter press) configured to at least partiallyseparate a precipitated salt from the remainder of a suspensioncontaining the precipitated salt (e.g., a solid-containing stream). Insome such embodiments, at least a portion of the liquid within thesolid-containing stream can be transported through the filter, leavingbehind solid precipitated salt (e.g., a filter cake). As onenon-limiting example, a Larox FP 2016-8000 64/64 M40 PP/PP Filter(Outotec, Inc.) may be used as the filter. The filter may comprise, incertain embodiments, a conveyor filter belt which filters the salt froma suspension containing the salt. In some cases, for example, thefiltration apparatus may be fluidly connected (e.g., fluidly directlyconnected) to the suspended solids removal apparatus. For example, incertain embodiments, a solid-containing stream may be flowed (e.g.,pumped) from the suspended solids removal apparatus (e.g., a clarifier)to the filtration apparatus.

In some embodiments, a solid-containing stream from the suspended solidsremoval apparatus may be pumped to the filtration apparatus by one ormore pumps (e.g., air diaphragm pumps). In certain embodiments, the oneor more pumps may initially pump at a relatively low pressure and mayautomatically increase the pressure as flow rate drops due to collectionof solids in the filtration apparatus. In some cases, such a process maybe advantageous. For example, in embodiments where the filtrationapparatus comprises one or more filter presses, such a process mayadvantageously reduce filter cloth blinding (e.g., embedding ofparticles in a filter cloth) and result in formation of more consistentfilter cakes. In certain cases, a liquid component of thesolid-containing stream may be rejoined with other liquid streams in thepretreatment system, desalination system, and/or precipitation apparatusafter passing through the filtration apparatus.

In some cases, one or more buffer tanks may be positioned between thesuspended solids removal apparatus and the filtration apparatus. Thepresence of one or more buffer tanks between the suspended solidsremoval apparatus and the filtration apparatus may, in some cases,advantageously provide buffer volume in the event that components of thefiltration apparatus (e.g., one or more filter presses) are undergoing acleaning cycle.

In some cases, a component of the filtration apparatus (e.g., a filterpress) may undergo a cleaning cycle when it is full. In certain cases, afiltration apparatus component may be considered to be full when theflow rate drops below a threshold level at a certain pumping pressure.In certain cases, when a filtration apparatus undergoes a cleaningcycle, flow may be rerouted to one or more buffer tanks to continuefluid circulation and prevent solid buildup. In some cases, the cleaningcycle begins by pumping clean brine into the filtration apparatuscomponent to flush out soft filter cake. The filtration apparatuscomponent may then be blown down. In some cases, the filter cake may bedried. For example, in certain cases, the filter cake may be air driedby blowing compressed air through the cake. It may be advantageous insome cases for the filter cake to be air dried in order to reduce itsliquid content. In some cases, compacted filter cake may be storedand/or disposed (e.g., in a dumpster).

Various of the unit operations described herein can be “directly fluidlyconnected” to other unit operations and/or components. As used herein, adirect fluid connection exists between a first unit operation and asecond unit operation (and the two unit operations are said to be“directly fluidly connected” to each other) when they are fluidlyconnected to each other and the composition of the fluid does notsubstantially change (i.e., no fluid component changes in relativeabundance by more than 5% and no phase change occurs) as it istransported from the first unit operation to the second unit operation.As an illustrative example, a stream that connects first and second unitoperations, and in which the pressure and temperature of the fluid isadjusted but the composition of the fluid is not altered, would be saidto directly fluidly connect the first and second unit operations. If, onthe other hand, a separation step is performed and/or a chemicalreaction is performed that substantially alters the composition of thestream contents during passage from the first component to the secondcomponent, the stream would not be said to directly fluidly connect thefirst and second unit operations.

It should be understood that, in embodiments in which a single unit isshown in the figures and/or is described as performing a certainfunction, the single unit could be replaced with multiple units (e.g.,operated in parallel) performing a similar function. For example, incertain embodiments, any one or more of the separation apparatus,suspended solids removal apparatus, ion-removal apparatus, pH adjustmentapparatus, VOM removal apparatus, and/or filtration apparatus couldcorrespond to a plurality of separation apparatuses, suspended solidsremoval apparatuses, ion-removal apparatuses, pH adjustment apparatuses,VOM removal apparatuses, and/or filtration apparatuses (e.g., configuredto be operated in parallel).

As particular examples, in some embodiments, the pretreatment systemcomprises a single unit that acts as both a separation apparatus and anion-removal apparatus. In some embodiments, the system comprises asingle unit that acts as both a separation apparatus and a suspendedsolids removal apparatus. In certain embodiments, the system comprises asingle unit that acts as both a separation apparatus and a pH adjustmentapparatus. In certain embodiments, the system comprises a single unitthat acts as both a separation apparatus and a VOM removal apparatus. Incertain embodiments, the system comprises a single unit that acts asboth a separation apparatus and a filtration apparatus. As additionalexamples, in some embodiments, the system comprises a single unit thatacts as both an ion-removal apparatus and a suspended solids removalapparatus. In certain embodiments, the system comprises a single unitthat acts as both an ion-removal apparatus and a pH adjustmentapparatus. In certain embodiments, the system comprises a single unitthat acts as both an ion-removal apparatus and a VOM removal apparatus.In certain embodiments, the system comprises a single unit that acts asboth an ion-removal apparatus and a filtration apparatus. As stillfurther examples, in some embodiments, the system comprises a singleunit that acts as both a suspended solids removal apparatus and a pHadjustment apparatus. In some embodiments, the system comprises a singleunit that acts as both a suspended solids removal apparatus and a VOMremoval apparatus. In some embodiments, the system comprises a singleunit that acts as both a suspended solids removal apparatus and afiltration apparatus. In some embodiments, the system comprises a singleunit that acts as both a pH adjustment apparatus and a VOM removalapparatus. In some embodiments, the system comprises a single unit thatacts as both a pH adjustment apparatus and a filtration apparatus. Insome embodiments, the system comprises a single unit that acts as both aVOM removal apparatus and a filtration apparatus. Units that performthree, four, or five of the functions outlined above are also possible.Of course, the invention is not necessarily limited to combinationunits, and in some embodiments, any of the separation apparatus, thesuspended solids removal apparatus, the ion-removal apparatus, the pHadjustment apparatus, the VOM removal apparatus, and/or the filtrationapparatus may be standalone units.

It may be advantageous, in some cases, for a system for producing aconcentrated brine stream to avoid producing solid material (e.g., solidsalt) or to reduce the amount of solid material produced, as it may beexpensive and/or complicated to dispose of certain solid materials.According to some embodiments, approximately about 70%, about 80%, about90%, about 95%, about 99% or about 100% by weight of the materialdischarged from the system for producing a concentrated brine stream issubstantially a liquid or a gas. In some embodiments, the concentrationof solid material is about 5000 mg/L or less, about 2000 mg/L or less,about 1500 mg/L or less, about 1000 mg/L or less, about 750 mg/L orless, about 500 mg/L or less, about 200 mg/L or less, about 100 mg/L orless, about 75 mg/L or less, about 50 mg/L or less, about 20 mg/L orless, or about 10 mg/L or less. In some embodiments, the concentrationof solid material is in the range of about 10 mg/L to about 5000 mg/L,about 10 mg/L to about 2000 mg/L, about 10 mg/L to about 1500 mg/L,about 10 mg/L to about 1000 mg/L, about 10 mg/L to about 750 mg/L, about10 mg/L to about 500 mg/L, about 10 mg/L to about 200 mg/L, about 10mg/L to about 100 mg/L, about 10 mg/L to about 75 mg/L, about 10 mg/L toabout 50 mg/L, about 0 mg/L to about 5000 mg/L, about 0 mg/L to about2000 mg/L, about 0 mg/L to about 1500 mg/L, about 0 mg/L to about 1000mg/L, about 0 mg/L to about 750 mg/L, about 0 mg/L to about 500 mg/L,about 0 mg/L to about 200 mg/L, about 0 mg/L to about 100 mg/L, about 0mg/L to about 75 mg/L, about 0 mg/L to about 50 mg/L, about 0 mg/L toabout 20 mg/L, or about 0 mg/L to about 10 mg/L. In some embodiments, asystem for producing a concentrated brine stream may producesubstantially no solid material.

In some embodiments, a transiently-operated desalination system mayproduce an amount of solid material. For example, in some cases, asystem for producing a concentrated brine stream may producesupersaturated brines. In certain embodiments, supersaturated brines canbe used to produce solid salt. In certain cases, it may be advantageousfor a system to produce solid salt, as it may be easier to dispose ofsolid salt than certain liquid and/or gas products.

In some embodiments, the system for producing a concentrated brinestream comprises a precipitation apparatus. In some cases, theprecipitation apparatus is fluidly connected to a desalination systemand is configured to receive a concentrated brine stream from thedesalination system. The precipitation apparatus is, in certainembodiments, configured to precipitate at least a portion of thedissolved salt from the concentrated brine stream to produce a productstream containing less of the dissolved salt relative to theconcentrated brine stream. For example, in FIG. 4, precipitationapparatus 418 can be configured such that at least a portion of the saltwithin concentrated brine stream 448 precipitates within precipitationapparatus 418 to produce substantially pure water stream 450, whichcontains less dissolved salt than concentrated brine stream 448.

The precipitation apparatus can be manufactured in any suitable manner.In certain embodiments, the precipitation apparatus comprises a vessel,such as a crystallization tank. The vessel may include an inlet throughwhich at least a portion of the concentrated brine stream produced bythe desalination system is transported into the precipitation vessel.The precipitation vessel may also include at least one outlet. Forexample, the precipitation vessel may include an outlet through whichthe water-containing stream (containing the dissolved salt in an amountthat is less than that contained in the inlet stream) is transported. Insome embodiments, the precipitation vessel includes an outlet throughwhich solid, precipitated salt is transported.

In some embodiments, the crystallization tank comprises a low shearmixer. The low shear mixer can be configured to keep the crystals thatare formed mixed (e.g., homogeneously mixed) in the brine stream.According to certain embodiments, the vessel is sized such that there issufficient residence time for crystals to form and grow. In certainembodiments, the precipitation apparatus comprises a vessel whichprovides at least 20 minutes of residence time for the concentratedbrine stream. As one non-limiting example, the vessel comprises,according to certain embodiments, a 6000 gallon vessel, which can beused to provide 24 minutes of residence in a 500 US barrel per day freshwater production system.

Those of ordinary skill in the art are capable of determining theresidence time of a volume of fluid in a vessel. For a batch (i.e.,non-flow) system, the residence time corresponds to the amount of timethe fluid spends in the vessel. For a flow-based system, the residencetime is determined by dividing the volume of the vessel by thevolumetric flow rate of the fluid through the vessel.

In some embodiments the crystallization tank is fluidly connected to astorage tank. The storage tank may have, in some embodiments, a capacitythat is substantially the same as the capacity of the crystallizationtank. In certain embodiments, the crystallization tank and/or thestorage tank can be configured to accommodate batch operation of adownstream solid handling apparatus, which can be fluidly coupled to theprecipitation apparatus.

In some embodiments, the precipitation apparatus comprises at least onevessel comprising a volume within which the concentrated brine stream issubstantially quiescent. In some embodiments, the flow rate of the fluidwithin the substantially quiescent volume is less than the flow rate atwhich precipitation (e.g., crystallization) is inhibited. For example,the flow rate of the fluid within the substantially quiescent volume mayhave, in certain embodiments, a flow rate of zero. In some embodiments,the flow rate of the fluid within the substantially quiescent volume mayhave a flow rate that is sufficiently high to suspend the formed solids(e.g., crystals), but not sufficiently high to prevent solid formation(e.g., crystal nucleation). The substantially quiescent volume withinthe vessel may occupy, in some embodiments, at least about 1%, at leastabout 5%, at least about 10%, or at least about 25% of the volume of thevessel. As one particular example, the precipitation apparatus cancomprise a vessel including a stagnation zone. The stagnation zone maybe positioned, for example, at the bottom of the precipitation vessel.In certain embodiments, the precipitation apparatus can include a secondvessel in which the solids precipitated in the first vessel are allowedto settle. For example, an aqueous stream containing the precipitatedsolids can be transported to a crystallization tank, where the solidscan be allowed to settle. The remaining contents of the aqueous streamcan be transported out of the crystallization tank. While the use of twovessels within the precipitation apparatus has been described, it shouldbe understood that, in other embodiments, a single vessel, or more thantwo vessels may be employed. In certain embodiments, the desalinationsystem can be operated such that precipitation of the salt occurssubstantially only within the stagnation zone of the precipitationvessel.

In some embodiments, the precipitated salt from the precipitationapparatus is fed to a solids-handling apparatus. The solids-handlingapparatus may be configured, in certain embodiments, to remove at leasta portion of the water retained by the precipitated salt. In some suchembodiments, the solids-handling apparatus is configured to produce acake comprising at least a portion of the precipitated salt from theprecipitation apparatus. As one example, the solids-handling apparatuscan comprise a filter (e.g., a vacuum drum filter or a filter press)configured to at least partially separate the precipitated salt from theremainder of a suspension containing the precipitated salt. In some suchembodiments, at least a portion of the liquid within the salt suspensioncan be transported through the filter, leaving behind solid precipitatedsalt. As one non-limiting example, a Larox FP 2016-8000 64/64 M40 PP/PPFilter (Outotec, Inc.) may be used as the filter. The filter maycomprise, in certain embodiments, a conveyor filter belt which filtersthe salt from a suspension containing the salt.

In some embodiments, the desalination system comprises a transportdevice configured to transport precipitated salt away from theprecipitation apparatus. For example, in certain embodiments, a pump isused to transport a suspension of the precipitated salt away from theprecipitation apparatus. In other embodiments, a conveyor could be usedto transport precipitated salt away from the precipitation apparatus. Incertain embodiments, the transport device is configured to transport theprecipitated salt from the precipitation apparatus to a solids-handlingapparatus.

The following examples are intended to illustrate certain embodiments ofthe present invention, but do not exemplify the full scope of theinvention.

Example 1

In this example, a fluidic circuit comprising a feed tank and adesalination system is described.

As shown in FIG. 6, system 600 for producing a concentrated brine streamcomprised feed tank 602 having a volume of 7,000 gallons, HDHdesalination system 604 having a production rate of 500 barrels/day, andliquid conduit 606. In addition, system 600 comprised pump 608, inletvalve 610, discharge valve 612, and recirculation valve 614.

In operation, inlet valve 610 was opened, and discharge valve 612 andrecirculation valve 614 were closed. Clean brine (e.g., brine that hasundergone pretreatment to remove one or more substances) having an NaClconcentration of 14 wt % entered feed tank 602 through an inlet at atemperature of 60° F. and a flow rate of 620 gallons per minute (gpm).Inlet valve 610 was then closed, and recirculation valve 614 was opened.The clean brine was pumped from feed tank 602 to desalination system 604by pump 608, and the clean brine entered desalination system 604 at atemperature of 130° F. and a flow rate of 620 gpm. A pure water outletstream (e.g., a water stream having an NaCl concentration of about 0 wt%) exited desalination system 604 at a temperature of 140° F. and a flowrate of 25 gpm. A concentrated brine stream having an NaCl concentrationof 15 wt % also exited desalination system 604, with the concentratedbrine stream having a temperature of 135° F. and a flow rate of 593 gpm.The concentrated brine stream recirculated through conduit 606 to feedtank 602. The concentrated brine stream continued to recirculate throughsystem 600, with the NaCl concentration of the concentrated brineincreasing with every cycle, until the concentrated brine stream had anNaCl concentration of 26 wt %. Upon reaching an NaCl concentration of 26wt %, discharge valve 612 was opened and recirculation valve 614 wasclosed, and the recirculated concentrated brine was discharged fromsystem 600 at a temperature of 135° F. and a flow rate of 593 gpm.

Example 2

In this example, a system for producing a concentrated brine stream isdescribed, where the system comprises two feed tanks, a desalinationsystem, and a heat exchanger.

As shown in FIG. 7, system 700 comprises first feed tank 702 having avolume of 7,000 gallons, second feed tank 704 having a volume of 7,000gallons, HDH desalination system 706 having a production rate of 500barrels/day, and heat exchanger 708. In addition, system 700 comprisesfirst pump 710, second pump 712, and valves 714, 716, 718, 720, 722,724, 726, 728, 730, and 732.

In operation, first feed tank 702 is initially full of clean brine(e.g., brine that has undergone pretreatment to remove one or moresubstances) having an NaCl concentration of 14 wt %, and all valvesexcept valves 714 and 718 are closed. The clean brine in first feed tank702 is pumped to desalination system 706 by pump 712, and the cleanbrine enters desalination system 706 at a temperature of 130° F. and aflow rate of 620 gpm. A stream of substantially pure water (e.g., waterhaving an NaCl concentration of about 0 wt %) exits desalination system706 at a temperature of 140° F. and a flow rate of 25 gpm. A stream ofconcentrated brine having an NaCl concentration of 15 wt % exitsdesalination system 706 at a temperature of 135° F. and a flow rate of593 gpm. The stream of concentrated brine is returned to first feed tank702. Valves 726 and 732 are opened, and an amount of clean brine (e.g.,to compensate for the substantially pure water that was removed) isadded to first feed tank 702 at a temperature of 60° F. and a flow rateof 620 gpm. Valves 726 and 732 are then closed, and the concentratedbrine stream continues to recirculate through a fluidic circuitcomprising first feed tank 702 and desalination system 706. The NaClconcentration of the concentrated brine stream continues to increasewith each cycle. When the NaCl concentration of the concentrated brinestream reaches 26 wt %, valves 714 and 718 are closed, and valves 722and 730 are opened. Valves 732 and 728 are also opened. The concentratedbrine stream is then discharged from first feed tank 702 through heatexchanger 708. The concentrated brine stream enters heat exchanger 708at a temperature of 130° F. and a flow rate of 620 gpm. At the sametime, a second clean brine stream having an NaCl concentration of 14 wt% enters heat exchanger 708 at a temperature of 60° F. and a flow rateof 620 gpm. In heat exchanger 708, heat is transferred from theconcentrated brine stream to the second clean brine stream. Afterflowing through heat exchanger 708, the concentrated brine stream exitssystem 700 at a temperature of 70° F. and a flow rate of 620 gpm, whilethe second clean brine stream flows to second feed tank 704 at atemperature of 120° F. and a flow rate of 620 gpm.

The second clean brine stream, having been heated to a temperature of120° F. in heat exchanger 708, flows into second feed tank 704. Aftertank 704 is filled, valves 728 and 732 are closed, and valves 716 and720 are opened. The second clean brine stream flows through desalinationsystem 706, and at least a portion of water is removed from the secondclean brine stream to form a second concentrated brine stream. Thesecond concentrated brine stream is recirculated through the fluidiccircuit comprising second feed tank 704 and desalination system 706. Thesecond concentrated brine stream flows between second feed tank 704 anddesalination system 706 until the second concentrated brine streamreaches an NaCl concentration of 26%. At that point, valves 716 and 720are closed, and valves 724 and 730 are opened. The second concentratedbrine stream is discharged from system 700 through heat exchanger 708while a third clean brine stream enters system 700 through heatexchanger 708 and is flowed to first feed tank 702, with heattransferring from the second concentrated brine stream to the thirdclean brine stream.

Example 3

In this example, a system for producing a concentrated brine stream thatis configured for primary and secondary heat recovery is described. Theconfiguration of the system is as shown in FIG. 3B.

In FIG. 3B, system 300 comprises HDH desalination unit 302, feed tank304, heat exchanger 308, and concentrated brine tank 356. Initially, HDHdesalination unit 302 is brought into operation. Brine circulatesthrough HDH desalination unit 302 at a rate of about 620 gpm. The brineis desalinated at a rate of about 25 gpm. Make-up brine is supplied toHDH desalination unit 302 at a rate of 25 gpm to maintain a constantvolume in the unit. As fresh water is separated from the recirculatedvolume and replaced with make-up brine, the salinity of the recirculatedbrine stream increases.

84 minutes after starting, the recirculated brine stream in HDHdesalination unit 302 reaches a target NaCl concentration of 25 wt %.Discharge of the recirculated brine stream begins. A valve connectingthe recirculation loop to the discharge header is opened, allowingconcentrated brine to discharge at a rate of about 350 gpm. A valvecontrolling the flow of makeup brine is opened, allowing make-up brineto enter the unit at a rate of about 350 gpm. A valve on therecirculation loop is then closed. Flow into the make-up header from thefeed pump is increased to a rate of 400 gpm. 350 gpm entered HDHdesalination unit 302.

The discharged concentrated brine flows through counter-flow heatexchanger 308, where heat is transferred from the concentrated brinestream to the make-up brine stream. The concentrated brine stream issubstantially cooled before exiting heat exchanger 308 and flowingthrough conduit 374 into concentrated brine tank 356. Make-up brine ispumped from feed tank 304 through heat exchanger 308, recovering thermalenergy from the concentrated brine stream. The heated make-up brineflows through conduits 362 and 364 to HDH desalination unit 302.

Once discharge is ended, flow through heat exchanger 308 is replaced bywarm concentrated brine from concentrated brine tank 356. The make-upbrine continues to flow through heat exchanger 308. A portion of themake-up brine (e.g., 25 gpm) is flowed to HDH desalination unit 302, andthe remainder (e.g., 325 gpm) is returned to feed tank 304. Accordingly,heat is exchanged between feed tank 304 and concentrated brine tank 356,bringing their temperatures towards an equilibrium.

Example 4

A system for producing a concentrated brine stream is described. Asshown in FIG. 8, system 800 comprises HDH desalination units 802A, 802B,and 802C, recirculation conduits 804A, 804B, and 804C, discharge headers806A, 806B, and 806C, inlet headers 808A, 808B, and 808C, feed tank 810,concentrated brine tank 812, and heat exchanger 814.

Initially, first HDH unit 802A is brought into operation. A brine streamis circulated through first HDH unit 802A at a rate of 620 gpm (e.g.,via recirculation conduit 804A). The brine stream is desalinated at arate of 25 gpm. Make-up brine is supplied to unit 802A at 25 gpm tomaintain a constant volume in first HDH unit 802A. As fresh water isseparated from the recirculated brine stream and replaced with make-upbrine, the salinity of the recirculated brine stream increases. Afterabout 29 minutes, while first HDH unit 802A continues to operate, secondHDH unit 802B is brought into operation. After another 29 minutes (58minutes total), while first HDH unit 802A and second HDH unit 802Bcontinue to operate, third HDH unit 802C is also brought into operation.

84 minutes after starting up, the brine recirculation loop in first HDHunit 802A reaches the target NaCl concentration of 26 wt %, anddischarge begins. A valve connecting the recirculation loop (e.g.,including recirculation conduit 804A) to discharge header 806A isopened, allowing concentrated brine to discharge at a rate ofapproximately 350 gpm. A valve controlling the flow of make-up brinethrough inlet header 808A is opened, allowing 350 gpm of make-up brineto enter the system. A valve on the recirculation loop is closed,reducing the recirculation flow from 620 gpm to 0 gpm. During this time,the total flow through inlet header 808A is 400 gpm. 350 gpm is fed tothe discharging unit (e.g., first HDH unit 802A), and 25 gpm make-upbrine is fed to each of the two remaining units (e.g., second HDH unit802B and third HDH unit 803C). Hot concentrated brine flows throughdischarge header 806A at a rate of 350 gpm. Some portion of thedischarged brine enters heat exchanger 814. On the other side of theheat exchanger, make-up brine is pumped from feed tank 810, through heatexchanger 814, then back into tank 810, such that some of the heat fromthe hot concentrated brine is transferred to feed tank 810. Cooledconcentrated brine enters concentrated brine tank 812, where it is mixedwith any of the hot concentrated brine that does not flow through heatexchanger 814. After about 3 minutes, the salinity of the dischargedbrine falls below 24%, and the valve connecting first HDH unit 802A tothe discharge header is shut, the valve connecting the first HDH unit tothe intake header is throttled to allow only 25 gpm in, and the valveregulating flow in the recirculation loop is opened to allow 620 gpm ofbrine. The source of hot concentrated brine to the heat recovery heatexchanger 814 is interrupted. Flow is replaced by warm brine fromconcentrated brine tank 812.

26 minutes after discharge from first HDH unit 802A ends, second HDHunit 802B reaches the target salinity of 26 wt % NaCl. The dischargeprocedure is the same as for first HDH unit 802A. 26 minutes afterdischarge from second HDH unit 802B ends, third HDH unit 802C reachesits target salinity of 26 wt % NaCl. The discharge procedure is the sameas for first HDH unit 802A. 26 minutes after discharge from third HDHunit 802C ends, first HDH unit 802A again reaches the target salinity of26 wt % NaCl.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,and/or methods, if such features, systems, articles, materials, and/ormethods are not mutually inconsistent, is included within the scope ofthe present invention.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Other elements may optionallybe present other than the elements specifically identified by the“and/or” clause, whether related or unrelated to those elementsspecifically identified unless clearly indicated to the contrary. Thus,as a non-limiting example, a reference to “A and/or B,” when used inconjunction with open-ended language such as “comprising” can refer, inone embodiment, to A without B (optionally including elements other thanB); in another embodiment, to B without A (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” and the like are to be understoodto be open-ended, i.e., to mean including but not limited to. Only thetransitional phrases “consisting of” and “consisting essentially of”shall be closed or semi-closed transitional phrases, respectively, asset forth in the United States Patent Office Manual of Patent ExaminingProcedures, Section 2111.03.

What is claimed is:
 1. A method for producing a concentrated brinestream, comprising: supplying a first liquid stream comprising water anda dissolved salt at an initial concentration to a fluidic circuitcomprising a desalination system, wherein the desalination systemremoves at least a portion of the water from the first liquid stream toproduce a first concentrated brine stream comprising water and thedissolved salt at a second concentration higher than the initialconcentration of the first liquid stream; recirculating the firstconcentrated brine stream through the fluidic circuit to remove at leasta portion of the water from the first concentrated brine stream, forminga recirculated first concentrated brine stream comprising water and thedissolved salt at a third concentration higher than the secondconcentration of the first concentrated brine stream; discharging therecirculated first concentrated brine stream from the fluidic circuitwhen the recirculated first concentrated brine stream reaches a densityof at least about 10 pounds per gallon, wherein discharging therecirculated first concentrated brine stream comprises flowing therecirculated first concentrated brine stream through a first portion ofa heat exchanger; supplying a second liquid stream comprising water anda dissolved salt at an initial concentration to the fluidic circuitcomprising the desalination system, wherein supplying the second liquidstream comprises flowing the second liquid stream through a secondportion of the heat exchanger, wherein heat is transferred from therecirculated first concentrated brine stream to the second liquid streamin the heat exchanger, and wherein the desalination system removes atleast a portion of the water from the second liquid stream to produce asecond concentrated brine stream comprising water and the dissolved saltat a second concentration higher than the initial concentration of thesecond liquid stream; recirculating the second concentrated brine streamthrough the fluidic circuit to remove at least a portion of the waterfrom the second concentrated brine stream, forming a recirculated secondconcentrated brine stream comprising water and the dissolved salt at athird concentration higher than the second concentration of the secondconcentrated brine stream; and discharging the recirculated secondconcentrated brine stream from the fluidic circuit when the recirculatedsecond concentrated brine stream reaches a density of at least about 10pounds per gallon.
 2. The method according to claim 1, wherein therecirculated first concentrated brine stream has a salinity of at leastabout 25% upon discharge from the fluidic circuit and/or therecirculated second concentrated brine stream has a salinity of at leastabout 25% upon discharge from the fluidic circuit.
 3. The methodaccording to claim 1, further comprising pre-treating the first liquidstream and/or the second liquid stream to remove at least a portion ofat least one scale-forming ion.
 4. The method according to claim 1,further comprising pre-treating the first liquid stream and/or thesecond liquid stream to remove at least a portion of a suspended and/oremulsified immiscible phase.
 5. The method according to claim 1, furthercomprising pre-treating the first liquid stream and/or the second liquidstream to remove at least a portion of suspended solids.
 6. The methodaccording to claim 1, further comprising precipitating at least aportion of the salt from the first concentrated brine stream and/or therecirculated first concentrated brine stream; and/or precipitating atleast a portion of the salt from the second concentrated brine streamand/or the recirculated second concentrated brine stream.
 7. A methodfor producing a concentrated brine stream, comprising: supplying a firstliquid stream comprising water and a dissolved salt at an initialconcentration to a feed tank; flowing the first liquid stream from thefeed tank to a fluidic circuit comprising a desalination system, whereinthe desalination system removes at least a portion of the water from thefirst liquid stream to produce a first concentrated brine streamcomprising water and the dissolved salt at a second concentration higherthan the initial concentration of the first liquid stream; recirculatingthe first concentrated brine stream through the fluidic circuit toremove at least a portion of the water from the first concentrated brinestream, forming a recirculated first concentrated brine streamcomprising water and the dissolved salt at a third concentration higherthan the second concentration of the first concentrated brine stream;discharging the recirculated first concentrated brine stream from thefluidic circuit when the recirculated first concentrated brine streamreaches a density of at least about 10 pounds per gallon, whereindischarging the recirculated first concentrated brine stream comprisesflowing the recirculated first concentrated brine stream through a firstportion of a heat exchanger to a concentrated brine tank; supplying asecond liquid stream comprising water and a dissolved salt at an initialconcentration to the feed tank, wherein supplying the second liquidstream comprises flowing the second liquid stream through a secondportion of the heat exchanger, wherein heat is transferred from therecirculated first concentrated brine stream to the second liquid streamin the heat exchanger; flowing the second liquid stream from the feedtank to the fluidic circuit comprising the desalination system, whereinthe desalination system removes at least a portion of the water from thesecond liquid stream to produce a second concentrated brine streamcomprising water and the dissolved salt at a second concentration higherthan the initial concentration of the second liquid stream;recirculating the second concentrated brine stream through the fluidiccircuit to remove at least a portion of the water from the secondconcentrated brine stream, forming a recirculated second concentratedbrine stream comprising water and the dissolved salt at a thirdconcentration higher than the second concentration of the secondconcentrated brine stream; discharging the recirculated secondconcentrated brine stream from the fluidic circuit when the recirculatedsecond concentrated brine stream reaches a density of at least about 10pounds per gallon, wherein discharging the recirculated secondconcentrated brine stream comprises flowing the recirculated secondconcentrated brine stream through the first portion of the heatexchanger to the concentrated brine tank; and flowing a first volume ofliquid from the concentrated brine tank to the first portion of the heatexchanger while flowing a second volume of liquid from the feed tank tothe second portion of the heat exchanger, wherein heat is transferredfrom the first volume of liquid to the second volume of liquid.
 8. Themethod according to claim 7, wherein the recirculated first concentratedbrine stream and/or recirculated second concentrated brine stream has asalinity of at least about 25% upon discharge from the fluidic circuit.9. The method according to claim 7, further comprising pre-treating thefirst liquid stream and/or the second liquid stream to remove at least aportion of at least one scale-forming ion.
 10. The method according toclaim 7, further comprising pre-treating the first liquid stream and/orthe second liquid stream to remove at least a portion of a suspendedand/or emulsified immiscible phase and/or at least a portion ofsuspended solids.
 11. The method according to claim 7, furthercomprising precipitating at least a portion of the salt from the firstconcentrated brine stream and/or the recirculated first concentratedbrine stream; and/or precipitating at least a portion of the salt fromthe second concentrated brine stream and/or the recirculated secondconcentrated brine stream.
 12. The method according to claim 1, whereinthe desalination system comprises one or more desalination units. 13.The method according to claim 12, wherein the one or more desalinationunits comprise a mechanical vapor compression unit, a multi-effectdistillation unit, a multi-stage flash unit, and/or a vacuumdistillation unit.
 14. The method according to claim 12, wherein the oneor more desalination units comprise two or more desalination units. 15.The method according to claim 14, wherein the two or more desalinationunits are the same or different types of desalination units.
 16. Themethod according to claim 7, wherein the desalination system comprisesone or more desalination units.
 17. The method according to claim 16,wherein the one or more desalination units comprise a mechanical vaporcompression unit, a multi-effect distillation unit, a multi-stage flashunit, and/or a vacuum distillation unit.
 18. The method according toclaim 16, wherein the one or more desalination units comprise two ormore desalination units.
 19. The method according to claim 18, whereinthe two or more desalination units are the same or different types ofdesalination units.
 20. A system for treating a liquid comprising waterand a dissolved salt at a first concentration, comprising: a bubblecolumn humidifier, comprising: a humidifier gas inlet in fluidcommunication with a source of a non-condensable gas; a humidifier gasoutlet; a humidifier liquid inlet in fluid communication with a sourceof the liquid; a humidifier liquid outlet; and a first stage comprisinga first bubble generator, a first liquid layer comprising at least aportion of the liquid, and a gas distribution region, wherein thehumidifier gas inlet is in fluid communication with the first bubblegenerator, wherein the bubble column humidifier removes at least aportion of the water from a stream of the liquid to produce a bubblecolumn humidifier liquid outlet stream comprising water and thedissolved salt at a second concentration greater than the firstconcentration, wherein the bubble column humidifier liquid outlet streamexits the bubble column humidifier through the humidifier liquid outlet;and a precipitator in fluid communication with the humidifier liquidoutlet of the bubble column humidifier, wherein the precipitatorprecipitates at least a portion of the dissolved salt from bubble columnhumidifier liquid outlet stream.